Recipe Courtesy Natalie MacMaster
Cream the butter and 2/3 cup sugar. Stir in vanilla.
Combine flour, baking powder and salt. Add alternately with milk, beginning and ending with dry ingredients.
Beat egg whites with 2 tbsp. sugar until stiff.
Fold in grated chocolate and stiffly beaten egg whites. Pour into greased 9 x 9-inch pan. Bake at 350 degrees F. for 25 minutes. Cool.
Combine icing sugar, egg yolks and butter until smooth. Spread over bottom layer.
Melt chocolate and butter. Mix well. Spread over middle layer. Refrigerate. When top layer is set. Cut and serve.