Preheat oven to 350. Grease one 15X10 jelly roll pan
Blend all ingredients at low speed until moistened, then mix for 2 minutes at medium speed. Pour into prepared pan. Bake at 350 for 25-30 minutes until toothpick inserted in center comes out clean. Cool completely and then frost with the following.
Make a frosting of: 2 cups powdered sugar, one third cup of softened margarine, 3 ounces of softened cream cheese, 1 tablespoon milk and 1 teaspoon vanilla extract. Combine and beat with electric mixer until smooth. Spread over cooled bars.