Recipe by: Mary M McBride's Encyclopedia of Cooking Preheat oven to 375 degrees; lightly grease two 23 cm layer pans. Sift flour once before measuring, then sift 3 times with baking powder, salt and baking soda. Cream butter until soft and smooth; gradually add sugar, creaming until light and fluffy. Add beaten egg yolks, then melted chocolate. Add milk alternately with dry ingredients, beating until smooth after each addition. Continue beating for two minutes. Fold in flavoring and stiffly beaten egg whites. Turn into prepared pans and bake for about 30 minutes. Turn out onto a wire rack to cool. Split layers in half horizontally. To prepare frosting, cream butter until soft; slowly stir in 2 cups sugar and the salt. Add additional sugar alternately with cream, beating thoroughly after each addition until creamy and smooth. Stir in walnuts with the last of the sugar. Beat in maple flavoring. Additional cream may be added to give frosting proper spreading consistency. Spread between layers, then frost top and sides of cake. ----