1/2 c. (1 stick) butter
1 1/2 c. sugar
1 tsp. vanilla
3 egg whites
2 c. sifted cake flour
1/4 c. instant dry milk
1/2 c. cocoa
1 tsp. baking powder
1 tsp. baking soda
1/4 tsp. salt
2 tbsp. vinegar
3/4 c. water

Preheat oven to 375 degrees. Cream butter and add sugar; continue to cream until fluffy. Add vanilla and mix well. Sift flour, instant dry milk, cocoa, baking powder, soda and salt. Combine the vinegar and water. Put in sifted dry ingredients and beat well; moderate speed for 2 minutes. Fold in beaten egg whites.

Pour batter into 2 greased and floured 9 inch cake pans or one 9 x 12 inch flat oblong pan. Bake in 375 degree oven for 30-35 minutes or until cake springs back when touched. Frost with Mocha Frosting.