1. Heat oven to 350°F. Grease and flour two 9-inch round baking pans. Beat egg whites in small bowl until foamy; gradually add 1/2 cup sugar, beating until stiff peaks form.
2. Combine remaining 1 cup sugar, flour, cocoa, baking soda and salt in large bowl. Add oil, buttermilk and egg yolks; beat until smooth. Gently fold egg whites into batter. Pour into prepared pans.
3. Bake 25 to 30 minutes or until cake springs back when touched lightly in center. Cool 5 minutes; remove from pans to wire racks. Cool completely.
4. Place one cake layer on serving plate; spread whipped topping over top. Sprinkle with half of toffee bits. Top with other layer. Spoon CHOCOLATE GLAZE over top of cake, allowing glaze to drip down sides. Sprinkle with remaining toffee. Store covered in refrigerator. Makes 12 servings.
CHOCOLATE GLAZE: Combine 1/2 cup sugar and 1/4 cup HERSHEY'S Dutch Processed Cocoa in small saucepan. Stir in 3 tablespoons light cream and 5 tablespoons butter or margarine. Cook over medium heat, stirring constantly, until mixture comes to a boil. Boil 1 minute. Cool to room temperature, stirring occasionally. About 3/4 cup.
*To sour milk: Use 1 tablespoon white vinegar plus milk to equal 1 cup.