Pre-heat the oven to 170'C.
Butter two 20cm cake tins, and line with baking parchment.
Top and tail the carrots (you will need about 2 large carrots), peel then grate. Set aside.
Zest and juice the lemon, and add to the grated carrots.
In a bowl, whisk together the gluten-free flour and baking powder to break up any lumps.
In a separate bowl, mix the eggs, oil and sugar together.
Combine the wet and dry ingredients together, whisking well to prevent the formation of lumps. Stir in the grated carrots.
Pour the batter into the two prepared moulds. Leave to rest for 10 minutes before baking.
Place in the oven, and bake for about 40 minutes, or until the cakes are golden brown and spongy.
When the cakes are cool to the touch, turn out from the cake tins, and leave to cool down completely before icing.
Lightly beat the soured cream so that it is smooth and creamy, and whisk in half the icing sugar.
Top one of the cakes with the cream, and place the second cake on top.
Finish with a dusting of the remaining icing sugar.
«Be aware that some baking powders contain wheat starch, and can cause discomfort if you are highly sensitive to wheat. Substitute the grated carrot for any other fruit or vegetable of your choice: chopped apples; cooked beetroot puree; courgette...»