Beat the butter and sugar fluffy cream and add one by one the three yolks. Mix the sifted flour with baking powder and coffee. Beat the egg whites to snow. To the oil mixture with stirring carefully consider adding smaller parts flour, walnuts and egg whites alternatively. Spread the bottom of a baking dish with baking paper and pour the dough. Preheat oven to 170 C and bake the base. Once cool, cut it horizontally into two parts and slightly syrupy them with cognac, dissolved in 1/3 cup water. In bowl mix flour, sugar, vanilla and lemon zest to the cream. Put the egg yolks and dilute with milk. Boil the cream to the required density. While still hot, divide the cream into two parts. In one place the broken white chocolate, the other black. Stir until melted chocolate and let cool. Beat cream fluffy cream and gently stirring add it to creams to lighten them. Spread one half with base creams alternatively. Dot with the other base. Other creams such as injection molding top grille.