1 c. butter
1 c. water
1/3 c. cocoa
2 c. flour
2 c. sugar
1 tsp. baking soda
1/2 tsp. salt
2 eggs
1/2 c. plain yogurt or sour cream

Heat oven to 375 degrees. Grease 15 1/2 x 10 1/2 x 1 inch jelly roll pan. Heat butter, water, and cocoa in a saucepan. Stir until mixed together. Remove from heat. In a mixing bowl stir together remaining ingredients. Add chocolate mixture. Pour in jelly roll pan. Bake 20 to 25 minutes or until toothpick inserted in center comes out clean. Cool and frost with Chocolate Yum Yum Frosting.