2 tbsp. cocoa
1 tbsp. + 2 tsp. hot water
1 c. powdered sugar
1 tbsp. oil

Dissolve 2 tablespoons cocoa in 1 tablespoon and 2 teaspoons hot water. Add 1 tablespoon oil, then blend in 1 cup powdered sugar. If needed, add more sugar to thicken or water to thin for desired consistency. I usually double the recipe for a 13x9 cake in the pan.