Checkerboard Cake

Grease and flour three 8 x 1 1/2-inch round baking pans. In a bowl combine flour, baking powder, soda, and 1/2 teaspoon salt. In a very large bowl beat shortening with an electric mixer on medium speed for 30 seconds. Add 1 2/3 cups of sugar and vanilla; beat till combined. Alternately add flour mixture and buttermilk, beating after each addition just till combined. Thoroughly wash beaters. Beat egg whites on medium until soft peaks form (tips curl). Gradually add remaining sugar, beating on medium to high till stiff peaks form (tips stand straight). Gently fold half on the egg white mixture into beaten mixture. Fold int the remaining egg white mixture. Spoon half of the batter (about 3 1/4 cups) into a bowl. Sift cocoa powder over remaining batter. Stir in the 1 tablespoon milk Set 3/4 cup of white batter aside. Spoon 1 1/4 cups of remaining white batter around the outer edge of each of two of the prepared pans. Spoon 3/4 cup of chocolate batter in a ring right next to the outer edge of white batter in each of the pans. Spoon half of the remaining white batter in the center of each pan. In the third pan, using 1 1/4 cups of chocolate batter, make an outer ring. Using the reserved 3/4 cup white batter, make inner ring. Fill center with the remaining chocolate batter. Bake at 350F degrees about 25 minutes or till cakes test done. Cool in pans about 10 minutes. Remove and cool. Place a cake layer with a white outer ring on serving plate. Frost top with 1/2 cup frosting. Place cake layer with chocolate outer ring on top. Frost top with 1/2 cup frosting. Top with remaining layer. Frost sides and top with remaining frosting. Serves 16. Chocolate Frosting Beat together 1/4 cup margarine and 2 cups sifted powdered sugar. Beat in 3 squares (3 ounces) unsweetened chocolate, melted and cooled; 1/2 cup milk; and 1 teaspoon vanilla. Beat in 2 1/2 to 3 cups sifted powdered sugar to reach desired consistency. Makes 4 cups.