Add the butter, egg yolk, sugar and grated lemon peel to approx. Mix for 1/2 hour. Beat the egg whites to a stiff foam. Mix the suto powder into the list and gently mix it into the dough together with the foam. Grease the baking tray with butter, flour it and pour the dough into it. Place the cherries that have been washed and dried in a kitchen towel. Fry it in a preheated oven on moderate heat. Leave to cool and slice.