Three quarters of softened butter are whipped with powdered sugar while gradually adding egg yolks. Next, we add lemon zest and while pouring in milk, we mix. Then, gradually fold in sifted flour with baking powder. With gradual addition of granulated sugar, we whip egg whites to a firm peak and gently fold them into the prepared butter mixture with the other ingredients. The finished batter is spread into a buttered and floured enameled baking pan (max. height 60 mm). This is topped with fruit and baked until golden.