Preheat the oven to 180C/Gas4; butter a 30cm round cake tin that is 5cm deep and line the base with greaseproof paper
Coarsely chop the nuts in a food processor
Beat the butter and sugar together until pale and light; add the egg yolks, one by one, beating well
In a separate bowl, beat the ricotta lightly with a fork; add the lemon zest and the chopped nuts
In a third bowl, whisk the egg whites until they form soft peaks
Fold the egg yolk and butter mixture into the ricotta; sift in the flour and fold it in
Finally fold in the whisked egg whites; spoon into the prepared tin and bake for 35 minutes or until set
Remove the cake from the tin to a plate and leave for 5 minutes then, while it is still warm, cover with the grated chocolate, which will immediately melt
Servings 0