Crumble the biscuits until sandy. It's quickest to do this in a food processor, but you can also do it by putting the biscuits in a ziplock bag and bashing with a rolling pin.
Pour in the melted butter and mix.
Empty the mixture into a loose-bottomed nonstick tin. I used a 23cm tin here to give a shallow cheesecake. A narrower tin will work fine if you prefer a taller cheesecake.
Press down with the back of a spoon until even and firm. Cook in the oven for just 5 minutes. Take it out of the oven and set it aside.
Make the filling
In a heatproof bowl, melt the chocolate in the microwave in 30-second blasts. Set aside to cool.
Put the cream cheese, instant coffee, cream and sugar in a large bowl. Whisk until smooth.
Add the melted, cooled chocolate and whisk through.
Add the eggs and flour, whisk again.
Pour the mixture on top of the biscuit base and gently level off.
Bake in the oven for 30-35 minutes until firm but slightly wobbly. If you're using a much narrower tin (e.g. 18cm) it will take 40-45 minutes, since it'll take longer for the middle to cook.
Take out the oven, and let it cool for 5 minutes. Run a knife around the edges of the cheesecake. This will ensure it doesn’t stick to the sides, causing the cheesecake to crack as it cools.
Allow to cool completely in the tin at room temperature, then pop in the fridge overnight (or as long as you can stand to wait).
Simply release from the tin, slice and transfer to plates.
I like to scatter with a few roasted coffee beans for extra coffee aroma.
The best place to store this coffee cheesecake is in the fridge in a sealed container or covered well with food wrap.Assuming you've used freshly opened cream and cream cheese, this cheesecake will keep for up to five days when stored correctly. Make sure to check the Use By dates on the cream and cream cheese to make sure they are within this time.