Slow-cooked lamb and sweet potato casserole

You'll love this deliciously warming lamb and sweet potato casserole, made with sweet potato, lamb and green beans, gently spiced with Moroccan notes and slow-cooked until the lamb melts in the mouth.

This slow-cooked lamb and sweet potato casserole simple, cost-effective cooking. We're talking minimal fuss and maximum taste; one-pot cooking, slow cookers and big bowls of delicious grub.

With this in mind, I used cheaper cuts of lamb in my recipe, but it doesn't mean even a jot of sacrifice on flavour, because we're cooking this lamb low and slow for a perfectly sumptuous dish.

You'll see that I've also included instructions on how to make an apricot jewelled couscous to pair beautifully with your casserole. I guess that's strictly an extra pot, but all the main cooking happens in the main casserole dish, I promise :)

Let's get cooking!

Instructions

Preheat the oven to 140C/275F/120C fan. Make up the marinade by mixing the cumin, ginger, cinnamon, coriander, cayenne, allspice, cloves, salt and 1 tbsp olive oil in small bowl.

Place the lamb in one bowl. Place the onions, garlic and sweet potato in another bowl with a tbsp olive oil.

Divide the marinade between the two bowls. Mixing and rubbing with your hands to coat evenly.

Heat the vegetable oil in a large, casserole dish (make sure it has a lid as you’ll need that later). When the oil sizzles, add the meat.

When the meat is just browned, add the marinated vegetables and fry for a couple more minutes, stirring well.

Add the stock, bring to a simmer, then place the lid on the casserole dish and put it in the oven.

Leave to slow cook for 1 hour 45 minutes, then remove from the oven, add the green beans on top, then put back in the oven for a final 15 minutes.

Meanwhile, place the couscous, apricot pieces and a crumbled stock cube in a heatproof bowl and stir in the boiling water. Cover and leave for 5 minutes, then uncover and fluff up with a fork.

Retrieve the casserole from the oven, the beans should be steamed but still crunchy.

Serve your slow-cooked lamb and sweet potato casserole to the table with a generous sprinkling of freshly chopped parsley. Enjoy!

What are your favourite ways to prepare a simple lamb meal? Try my slow cooked lamb korma recipe.

Pointers, tricks and troubleshooting tips for the perfect slow-cooked lamb and sweet potato casserole

Is lamb and sweet potato casserole easy to make?

This casserole is very easy to make and only takes around 15 minutes to prepare - the rest of the time can be spent making a delicious side (such as the suggested apricot jewelled couscous), or simply putting your feet up and waiting for the fantastic flavours to develop in the oven.

Will I need any special equipment for this lamb and sweet potato casserole?

Outside of a casserole dish there isn't anything you wouldn’t find in a standard kitchen. You doesn't necessarily have to use a cast iron casserole dish either. You can use a frying pan for browning the meat and veg before transferring the ingredients into a glass or ceramic casserole dish - either is fine as long as it has a lid.

Is this lamb and sweet potato casserole suitable for vegetarians? Is it suitable for vegans?

This casserole is not suitable for vegetarians or vegans and it uses lamb - however you could also swap this out for a vegetarian or vegan alternative. 

In the UK I have seen vegetarian or vegan mock lamb koftas as well as as a lamb strips and meat alternatives for Turkish style kebabs, so you have a lot of choice in potential substitutes. You can happily use something that's pre-flavoured as long as you think the flavours would be complementary with this dish.

Another option is wrap 2-4 aubergines in tin foil and roast the oven on high for 30 minutes or until starting to soften considerably, allow to cool a little, cut into pieces and use that instead of meat.

Is this lamb and sweet potato casserole gluten-free?

For the casserole itself, as you make sure to check all of the ingredients it is absolutely possible to make a gluten-free version of this dish. It's always best to check the packaging on everything you buy to make sure it's gluten-free, but be especially mindful when it comes to the vegetable stock as these will usually contain gluten - so make sure to get a gluten-free option. Spices can also have gluten-containing ingredients, or be produced in a factory that can't guarantee cross contamination does not occur, so again read the labels.

The couscous is a different story, as the variety you will find in the supermarkets in the UK will almost always be made from durum wheat based semolina, which contains gluten. However, there are gluten-free alternatives available in many larger UK supermarkets (usually made with maize), or you can also use quinoa as an alternative.

Is this lamb and sweet potato casserole healthy?

There's plenty of goodness in the vegetables and the lamb, including a good amount of protein, fibre and healthy fats. That means this is a great dish to serve whenever you fancy making it.

If you're looking to reduce calories I would reduce the couscous in favour of more casserole as its high carb count means it makes up over half the calories in this dish by default.

Is this lamb and sweet potato casserole safe to eat while pregnant?

As long as all the ingredients are in good condition, and the casserole has been prepared and cooked hygienically then this dish should be fine to eat whilst pregnant.

In the UK the NHS has some fantastic guidance on foods to avoid when pregnant.

This website does not offer medical advice. Please speak to a health professional if you have any questions

Is this lamb and sweet potato casserole suitable for babies and toddlers?

This recipe is suitable for babies and toddlers over 1 year old - as long as you forgo the vegetable stock in the casserole and the stock cube in the couscous to reduce the salt (which isn’t good for a baby’s kidneys). 

Also make sure that anything you are serving to babies or toddlers is appropriately sized and won't pose a choking hazard, so cut up the vegetables accordingly and thoroughly break up and cut the lamb into very small pieces before serving.

Children's palettes are different from that of an adult and develop slowly over time, so you may find that the spices used here are too strong and need to be reduced, but it varies heavily from one child to the next and in large part comes down to what they're used to.

Always keep babies supported upright while eating and supervise your baby when they’re eating in case they start to choke.

The NHS has some great advice on what to feed young children. If you are unsure, check with your health professional. This website does not give medical advice.

What goes well with lamb and sweet potato casserole?

The mixture of casserole and couscous should be plenty to make a well-rounded, tasty and nutritious meal, but if you wanted to you could throw in some flatbread into the oven to warm up through. This would be a tasty addition and and help you to sop up anything left on the plate.

If you fancy making your flatbread from scratch then the recipe that makes up part of this flatbread wrap is super quick to make and very tasty.

Can I make this lamb and sweet potato casserole without some of the spices?

While it's best to use all the spices this recipe contains if possible if you don't have one or two of them available you can leave it out and still end up with a very tasty dish.

If you have the non-ground version of any of the spices a you happily use whole seeds (if possible crush them in a pestle and mortar).

Can I add extra vegetables to this lamb and sweet potato casserole?

One of the best things about casseroles is that you can chop and change the ingredients to whatever you fancy or have to hand and almost always end up with something fantastic.

Vegetables that would work particularly well in this casserole would be onion, peppers, aubergines and courgettes. Chickpeas would also make a fine addition.

I haven't got lamb, can I use another meat?

While lamb really compliments the flavours of this dish other types of meat would work too.

If using beef you should be able to keep the recipe as is, if using chicken I would try to use thighs and legs rather the breasts as they will keep juicy during cooking, whereas breasts will likely dry out and become tough.

How should I store lamb and sweet potato casserole?

To store this casserole just make sure that you get it cooled down to room temperature, in an airtight container and in the fridge or freezer within two hours of taking it out of the oven.

A casserole dish will retain a lot of heat even out of the oven, so I would place anything that you know you will be storing for later in an air-tight container as soon as possible, which will cool the casserole faster. While cooling, rest the lid on top, but at a slight angle to allow steam to escape, before firmly shutting when going in the fridge/freezer.

How long does this lamb and sweet potato casserole keep?

If refrigerated and cooled down within two hours of making it should last for up to two days in the fridge.

If going into the freezer it should last for up to three months before you notice any drop in taste or texture upon reheating.

Can I leave this lamb and sweet potato casserole out on the counter?

No, once cooked this casserole should be eaten immediately or stored in the fridge or freezer. Leave it on the counter will let dangerous bacteria to multiply too quickly. See below for tips on how to refrigerate and freeze your casserole correctly.

Can I keep this lamb and sweet potato casserole in the refrigerator?

This casserole keeps very well in the fridge. In fact, I find that the flavours continue to develop so it's just as delicious if not more so when heated up the next day.

Just make sure to place your casserole in an airtight container then let it cool down to room temperature before storing in the fridge. Do this within 2 hours of taking it out of the oven and it will last for up to two days. 

Can I freeze this lamb and sweet potato casserole?

This casserole should freeze well. To freeze, just make sure that you get it cooled down to room temperature, in an airtight container and in the freezer within two hours of taking it out of the oven.

Before freezing also have a quick think about if you actually want to defrost the whole casserole, or would prefer to defrost it in multiple servings. It’s important to plan ahead as breaking it up after freezing is difficult. It's also because the casserole can only be reheated once and shouldn't be left to defrost in the fridge for more than a day at most.

With that in mind, if you wish to freeze your casserole into more manageable sized portions (or even individual servings) now is the time to do it. Simply place some of the casserole into smaller containers (or even distributed in a muffin tray) then freeze. Once frozen you can transfer the casserole servings into a single freezer bag for easy storage and to take up less space.

Make sure to label and date your containers.

To reheat your casserole it's best to get it back up to fridge temperature, so leave it to defrost in the fridge overnight. See below for more info.

What is the best way to reheat this lamb and sweet potato casserole?

Using a microwave is likely the quickest and simplest way of reheating a single portion or two of casserole. All you have to do is place it in a microwave-safe container with the lid on but not shut (so steam can escape), and cook on a low-medium setting. Make sure it is piping hot all the way through by first cooking it for a minute then giving it 30 second bursts until ready. Remember the centre of larger chunks of lamb will take longer to come up to temperature, so make sure to check everything is nice and hot before serving.

If you prefer, you can also reheat a serving or two casserole on the hob by placing it in a saucepan with a tablespoon or two of water and cooking over a low heat until it is hot all the way through. Keep a lid on the saucepan as this will heat everything more evenly, and be sure to check on it often to make sure it is not sticking to the bottom of the pan.

Finally, if you are planning on reheating a few serverings or whole casserole I would recommend doing it in the oven. If it has been frozen make sure it has been fully defrosted in the fridge first, which will likely take at least 12 hours. 

Preheat the oven to 170C/340F before placing the covered casserole (either with a lid or tinfoil) into the oven. How long the casserole will take to cook through will vary depending on its size, container type and ingredients used. I would check after 15 minutes and then keep checking every 5 minutes or so until fully cooked through. Remember to check the internal temperature of the lamb pieces are piping hot - ideally with a thermometer, where they should be at least 73C.

Why did my sweet potato casserole taste bland?

I find casseroles are excellent at bringing out the natural flavours of veg and meat, which combined with the many spices in this particular casserole means you end up with something that packs plenty of flavour.

However, if you feel that the dish could do with a little more of any particular spice feel free to adjust the quantity to your taste. Also, make sure you have added enough salt to the dish, as a ‘bland’ taste can often be a case of simply being under seasoned.

Can I make this lamb and sweet potato casserole in a different quantity?

You can make casserole in almost any quantity that you wish, as long as it will fit in your casserole dish. Simply use the recipe card that's located towards the bottom of this page, which has a handy slider that you can use to adjust serving sizes, which will also automatically change the needed quantities of each ingredient.

Can I make this lamb and sweet potato casserole in a tray?

You can happily use a glass or ceramic casserole dish with a lid, just make sure to use a normal frying pan to brown the meat and veg, then transfer it to the casserole dish.

However, I wouldn't recommend cooking this dish in anything that doesn't have a lid as  that's what keeps the moisture in, and also allows for the slight pressure increase, which helps to cook everything. 

Can I make this lamb and sweet potato casserole in the slow cooker?

This recipe should work very well in a the a slow cooker. It's up to you if you want to to brown the lamb and veg in a frying pan first, but I would highly recommend it. Cook on on low for about 8 hours or on medium for around 4 hours.

It's best not to check a slow cooker too often as you will let the steam escape and the temperature drop, but I would check around 3/4 of the way into cooking to see if your lamb has become perfectly tender. Try to break it apart with a clean fork, which should tell you what you need to know. Don't worry if your lamb still feels firm or even firmer than it did when it went in as red meat firms up a little in a slow cooker before slowly softening, so just give it more time.

How can I make sure this lamb and sweet potato casserole is perfectly cooked?

While it’s not a good idea to check on a casserole too often as opening the oven door will lower the temperature, and lifting the lid will let steam escape (which keeps everything moist and the temperature steady), the easiest way to make sure the meat and veg is cooked to your liking is to use a clean fork and check how soft the lamb and sweet potato is - it should almost break apart with a fork.

Why did my casserole turn out tough or undercooked?

If you find your casserole is undercooked -  which will be most obvious if the meat is still tough and/or the sweet potato is still hard - it is likely because your oven temperature wasn't set high enough, or it simply hasn't been left in the oven for long enough.

To remedy, check both the temperature of your oven is hot enough and simply place the casserole back in the oven and check every 10 minutes or so until soft, tender and delicious.

How can I add/change the flavours in this lamb and sweet potato casserole?

One of the best things about casseroles is their ability to turn cheaper, generally tougher cuts of meat into something with the perfect, tender texture while concentrating and enhancing other flavours.

They’re also super versatile and pretty forgiving when it comes to flavour combinations, which is part of the reason there are literally hundreds of different variations on the casserole that are popular throughout the world.

So if inspiration has struck you for a particularly delicious combination of ingredients, or you are just looking to use up some spare ingredients in your fridge or cupboard your casserole dish can be your best friend.

With that in mind here are some general tips and tricks when it comes to flavours to get you started.

Herbs and spices are what gives this slow cooked lamb its distinctive North African-inspired taste, so by switching these ingredients up you can completely change the taste of the dish. Ginger, garlic, thyme, curry powder and some scotch bonnets (not too much!) would take this dish in a more Caribbean direction, which I think would work fantastically, but have fun and experiment. Don’t forget fresh herbs are delicious in the dish, but also make a great garnish to sprinkle over it just before serving.

Fresh vegetables are an important part of pretty much all casseroles, but it never hurts to add more! Throw in whatever you have to hand and think will work, and if you want to, you can also marinate them as they have been in this recipe or fry them on the hob first, which will enhance their flavours.

Tinned vegetables work really well in casseroles, and their generally softer texture isn’t a problem, but if you’re worried about overcooking them you can also add them to the dish towards the end of cooking. Tinned veg are super handy when you want something that isn’t in season or readily available, as well as being a great way of using up anything that you find in the back of the cupboard.

Where does a casserole get its name from?

Rather confusingly a casserole can mean both the food being eaten and the container it’s been cooked in.

The casserole dish itself is generally a large, deep pan or bowl that is used to both cook the food and also used to serve it. Its name is most likely a French word, ‘casse’, which translates to ‘small saucepan’.

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