This basic frosting can be spread on the cookies or applied as a decorative piping with a pastry bag. If you plan to pipe the frosting, make it stiffer by adding a little less milk. If you don't have time to make the frosting, buy tubes of colored frosting.
Instead of rolling out your dough on a floured surface, roll it out between waxed paper. The cookies will stay moist because extra flour is not incorporated during the rolling process.
In a large bowl and using an electric mixer set at low speed, beat the confectioners' sugar, butter, and vanilla extract until it reaches spreading consistency. Add more sugar or a little milk, if necessary, to achieve the right texture. Stir in the food coloring until combined, if desired. Makes about 1-1/2 cups.