How to Make a Simple Cake Glaze: Melt 1/4 cup (4 tablespoons) of butter in a saucepan or microwave. Sift 2 cups of powdered sugar into a medium size bowl. Add the melted butter to the powdered sugar. Add 2 tablespoons of milk. If desired, 1/2 teaspoon of vanilla for flavor. Beat until smooth and creamy, adding a little more milk if necessary. Drizzle over a cooled cake. Tip: Substitute citrus juice for the milk and add a little grated zest for a citrus glaze.