1 thin-skinned lemon
2 small or 1 large thin-skinned lemons
2 level tsp baking powder
50²µ/1¾´Ç³ú caster sugar
275²µ/9¾´Ç³ú caster sugar
175g/7oz fondant icing sugar
175g/6oz icing sugar
275²µ/9¾´Ç³ú self-raising flour
275²µ/9¾´Ç³ú softened butter
50²µ/1¾´Ç³ú soft butter
4 free-range eggs
250g/9oz full-fat Italian mascarpone