Combine the first 6 ingredients in a large bowl; beat at medium speed of a mixer until smooth. Combine flour and next 5 ingredients; stir well. Add to milk mixture, beating well. Pour the cake batter into an 8-inch square baking pan coated with cooking spray. Bake at 350ºF.  for 25 minutes or until a wooden pick inserted in center comes out clean. Let cool in pan 10 minutes on a wire rack; remove from pan, and cool completely. Place the cake on a serving plate. Place a paper doily on top, and sprinkle powdered sugar over doily; carefully remove doily. Yield: 6 servings (serving size: 1 [4 x 2-1/2-inch] piece and 1 tablespoon whipped topping).