Yellow Sheet Cake with Chocolate Frosting

Cake:
Cooking spray
1 tbsp Better for Bread flour
1/2c margarine, melted
1 c light mayonnaise
1 1/2c brown sugar or Splenda
2 tsp vanilla extract
1/2c egg substitute
2 c baking mix #3 (see below)
3/4c soymilk

Chocolate frosting:
2-3 tbsp whole milk or soy milk, at room temperature
1 tsp vanilla extract, at room temperature
8 oz chocolate chips
8 tbsp boiling water
1-2 tbsp margarine, at room temperature
2- 4 c confectioner's sugar

Cake:
Preheat oven to 350°. Coat bottom of a 13 x 9-inch baking pan with cooking spray (do not coat sides of pan); line bottom of pan with wax paper. Coat wax paper with cooking spray; dust with 1 tablespoon flour. Set aside. Combine 1/2 cup margarine and mayonnaise in a large bowl, stirring with a whisk until well blended. Add sugar and 2 teaspoons vanilla. Beat with a mixer at medium speed 3 minutes or until well blended. Add egg substitute; beat 2 minutes or until well blended. Lightly spoon 2 cups baking mix into dry measuring cups; level with a knife. Add flour mixture and soymilk alternately to sugar mixture, beginning and ending with flour mixture; mix after each addition. Pour batter into prepared pan. Sharply tap pan once on counter to remove air bubbles. Bake at 350° for 30 minutes or until a wooden pick inserted in center comes out clean. Cool in pan 10 minutes on a wire rack; remove from pan. Carefully peel off wax paper; cool completely on wire rack.

Frosting:
The above measurements are approximate. Melt chocolate by adding boiling water and stir until smooth. Add vanilla and the sugar; stir until mixture is smooth. Or dissolve 1/2 cup cocoa in boiling water. A little cinnamon may be added. In a small bowl, whisk together the milk and vanilla. Pour in some powdered sugar. Add the milk mixture in 3 batches, waiting for each batch to be fully incorporated before adding the next (scrape the bowl down occasionally). Mix briefly until fluffy, and of the consistency you desire. Use more milk or sugar to get a larger batch, and a consistency you desire. Sugar will thicken, and a little milk will go to loosen. The margarine will allow a creamy consistency. May be stored, covered, in the refrigerator for 3 days.

Baking Mix #3

6 c Better for Bread flour
6 c Whole wheat flour
3 tbsp baking powder
2 tbsp baking soda
1 ½tsp salt
1 tsp baking soda

Mix all ingredients very well. Store in a cool dry area.