Patty's Cherry Birthday Cake

     Prepare cake mix according to package directions, using oil
     (or butter) and eggs, and reducing the water to 1/2 cup.
     Spread batter into a greased and floured 13x9x2-inch baking pan.
     Spoon cherry pie filling evenly over the batter, then swirl into the
     batter just enough to give a marbled effect.

     Bake cake at 350° until cake bounces back when lightly touched.
     Cool and cover with Cool Whip.