Heat oven to 350°F. Spray two 8 inch round pans with cooking spray. In bowl, stir flour, cocoa and baking soda. In saucepan, melt corn oil spread, stir in sugar. Remove from heat. Add milk, vinegar and vanilla to mixture in sauce pan, stir. Add dry ingredients, wisk until well blended. Pour evenly into pans. Bake 20 minutes or until wooden pick inserted comes out clean. Cool. Fill and frost top. Refrigerate. Light Cocoa Frosting: In small mixer bowl, stir together 1 envelope dry whipped topping mix, 1/2 cup cold skim milk, 1 T Hershey's C°Coa and 1/2 t vanilla extract. Beat on high speed of mixer about 4 minutes or until soft peaks form.