Texas Hot Fudge Frosting
["1 stick butter (1/2 c.)", "6 Tbsp. milk", "4 Tbsp. cocoa", "1 (16 oz.) box powdered sugar"]
["In a saucepan, melt butter over medium heat. Add cocoa and bring to a quick boil.", "Remove from heat.", "Add milk and bring to a boil again.", "Remove from heat.", "Add powdered sugar, about a third at a time and stir vigorously after each addition, until mixed thoroughly (it will be thick).", "Spread immediately on cake."]
["butter", "milk", "cocoa", "powdered sugar"]