Frosting for Sugar Cookies

This recipe is more of a guide.... The measurements are not exact because it was handed down from my grandma, and that's how she cooks.

-Put powdered sugar in a bowl large enough for mixing. Start with a cup, you can always add more.
-Add a small amount of vanilla extract--about 1/2 tsp.
-Add a small amount of milk--about 1 tsp. If you need more to stiffen the frosting, heat the milk first.
-Add butter or margarine, softened--approximately 1/2 stick. Add more butter to cut sweetness if necessary.

Cream with a hand mixer.

Once frosting is to your liking, divide into bowls if desired and add food coloring. Stir well. Do not let stand, frosting hardens fast.