15-1/2x10-1/2x1-inch jelly roll pan. 2. In small bowl, stir together cocoa and water until smooth. In large bowl, beat shortening, sugar, vanilla and eggs. Stir together flour, baking soda and salt; add alternately with buttermilk to shortening mixture. Stir in cocoa mixture. Spread batter into prepared pan. 3. Bake 28 to 30 minutes or until wooden pick inserted in center comes out clean. Cool in pan on wire rack. 4. Remove about 3/4 cup frosting; add food color to 1/2 cup frosting to tint desired shade of blue. Set aside the blue frosting and about 1/4 cup vanilla frosting. 5. Spread remaining vanilla frosting over top of cake. Spread blue frosting in upper left corner. Pipe stars in blue field with reserved 1/4 cup vanilla frosting. Shortly before serving, place strawberries in seven rows to represent red stripes of flag. About 15 servings. * To sour milk: Use 2 teaspoons white vinegar plus milk to equal 2/3 cup.Jm Hershey's is a registered trademark of Hershey Foods Corporation. Recipe may be reprinted courtesy of the Hershey Kitchens.