For Cake:
Stir together the flour, sugar, baking soda and cocoa. Add the remaining ingredients and mix well. Spread into a greased and floured 13 x 9 inch pan. Bake at 350 for 30 minutes. Cool completely before frosting.
For Frosting:
Mix all ingredients. Beat on high for 15 minutes.
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CHOCOLATE MAYONNAISE CAKE recipe