For the cake, place the two whole (or one large) lemons in a small saucepan, cover with water, bring to the boil and simmer for 20 minutes, or until very soft and tender. Drain, cut the lemons in ...

The whole cake should be covered in a thin, even layer, but it doesn't need to be perfect at this stage. Chill the cake for 15–20 minutes. This will help to seal in the crumbs and make the top ...