1. Heat oven to 350°F. Grease and flour three 9-inch round baking pans. (If only 2 pans are available, reserve one-third of batter in refrigerator while first 2 layers are baking.)
2. Beat egg whites in small bowl until foamy; gradually add 1/2 cup sugar, beating until stiff peaks form. Stir together flour, remaining 1 cup sugar, cocoa, baking soda and salt in large bowl. Add oil, buttermilk and egg yolks; beat until smooth. Gently fold egg white mixture into batter. Pour about 1-2/3 cups batter into each prepared pan.
3. Bake 18 to 20 minutes or until cake springs back when touched lightly in center. Cool 5 minutes; remove from pans to wire racks. (Bake remaining layer, if necessary.) Cool completely.
4. Wrap each layer separately in foil; freeze several hours or several days in advance of serving. Prepare ICE CREAM LAYERS. Remove cake and ICE CREAM LAYERS from freezer; peel off foil. On serving plate, alternately layer cake and ice cream layers, beginning and ending with cake. Wrap tightly; return to freezer. Just before serving, frost top of cake with whipped cream. Arrange fruit in decorative design on top; pipe on CHOCOLATE ROSETTES, if desired. 10 to 12 servings.
ICE CREAM LAYERS: Line two 9-inch round layer pans with foil; working quickly, evenly spread 1/2 gallon of your favorite flavor slightly softened ice cream into prepared pans. Cover tightly; freeze until firm.
CHOCOLATE CREAM ROSETTES: In small mixer bowl, stir together 1/4 cup sugar and 2 tablespoons HERSHEY'S Cocoa. Stir in 1/2 cup cold whipping cream and 1/2 teaspoon vanilla extract. Beat until stiff; spoon into decorating bag fitted with large rosette tip.
* To sour milk: Use 1 tablespoon white vinegar plus milk to equal 1 cup.