Combine all ingredients in a large resealable plastic bag; seal bag. Shake or mix until ingredients are thoroughly combined.
Store mix in plastic bag or in a tightly covered container. Shake or mix well before using.

To make Microwave Chocolate Cake, coat a 9-inch round microwaveable cake dish with cooking spray. In a large bowl, combine 2 cups Microwave Chocolate Cake Mix, 2 eggs, 1/2 cup mayonnaise, and 1/2 cup milk. Pour mixture into prepared cake dish. Microwave on medium power 9 minutes, turning once. Turn dish; microwave on high power for an aditional 3 minutes, or until a wooden toothpick inserted in center comes out clean. Cool in dish, and frost if desired.
To make Microwave Chocolate Cupcakes, line 6 microwaveable muffin pan cups with paper liners. In a medium bowl, combine 1 cup Microwave Chocolate Cake Mix, 1 egg, 1/4 cup mayonnaise, and 1/4 cup milk; stir until well blended. Spoon mixture into muffin cups. Microwave on high power 3 minutes, turning once. Cupcakes will appear moist; let cool an frost if desired.