In a large bowl, sift together the dry ingredients.
In a second bowl, beat together the wet ingredients, then add to the dry.
Finish by stirring in the grated carrots.
Divide evenly between 12 muffin cases in a muffin tray.
Bake in the oven at 190C (170C fan-assisted) for 25-30 minutes until firm and golden on top.
Let them rest in the tin for a few minutes, then transfer to a wire rack to cool completely.
Make the icing
Mix together the icing sugar and yoghurt for the frosting until smooth.
Drizzle a little over each muffin and top with a sprinkle of lemon rind.
Allow to set before eating.
This recipe is quite dependent on getting the right amounts of moisture and heat, so if your oven runs hot, or your wet ingredients are a little larger than average, you may get a slightly doughy centre. Check with a skewer pushed into the centre of each muffin to make sure they're cooked through.