Recipe for 6 Cups of Frosting. If you want enough frosting for more elaborate decorations make 6 cups, increase sugar to 1 3/4 cups, increase the flour to 5 tablespoons, increase the cornstarch to 3 tablespoons plus 2 teaspoons, increase the coconut milk to 1- 3/4cups, and increase the butter to 30 tablespoons.