3 1/4 c. unsifted all-purpose flour
2 1/4 c. sugar
1 c. unsweetened cocoa powder
1/2 c. cornstarch
1 tbsp. baking powder
1 tsp. baking soda
1 1/2 tsp. salt

Sift together all dry ingredients. Store in tightly covered container at room temperature. Stir before use.