The butter must be softened to start making the cake. Mix consistently all products: the butter, cocoa, sugar, egg, baking powder, salt, essence, flour, the walnuts. Peel the apples are cleaned seeds and cut into small cubes (not grated). Put the sliced ​​apples into the mixture and mix well (mixture is not smooth, it does not bother you). Pour the mixture into a buttered baking dish and bake at 180-200C about 40-45 minutes. Once the cake is ready can sprinkle it with powdered sugar or to namazhem with chocolate spread.