* 6 egg whites
* 100 g sugar
* 100 g butter
* 1 lemon
* 50 g ground walnuts
* 2 tablespoons chocolate balls
* 150 g flour
* vanilla essence
* 1 teaspoon baking powder
The soft butter at room temperature rubs the foam together with the sugar. Add lemon juice (and peel if you like) and mix. Then add flour mixed with baking powder, ground walnuts and chocolate balls. Whisk the egg whites with a pinch of salt, then incorporate them lightly into the butter composition.
Grease the cake tin with butter, pour the composition and put it in the oven over medium heat, until lightly browned on top. The toothpick is tested.
Leave to cool in the pan, then slice.