Add first 3 ingredients to beverage in bowl; quickly and firmly stir together for 20-30 seconds. DO NOT OVER MIX; batter will be lumpy. Spoon batter into greased muffin tins. Pour melted butter on top if desired. Bake at 375° for 25-30 minutes until muffins are golden brown. Remove from pan and cool on rack. Makes about 12 servings.