Place chocolate in top of a double boiler; bring water to a boil. Reduce heat to low; cook until chocolate melts. Cool. Combine chocolate, flour, baking powder, soda, salt, sugar, butter, water, and vanilla. Beat 2 minutes at medium speed of an electric mixer. Add eggs, and beat an additional 2 minutes. Pour batter into 4 greased and floured 9-inch round cakepans. Bake at 350 degrees for 15 to 18 minutes or until a wooden pick inserted in center comes out clean. Cool cake layers in pans 10 minutes; remove from pans, and let cool completely on wire racks. Place 1 layer on cake platter. Spread with half the Chocolate Filling. Place another cake layer on top, and spread with half the Whipped Cream Frosting. Repeat layers, and garnish with grated chocolate, if desired. ----