This simple cookie icing is easy to spread or pipe on and yields a nice glossy finish. It's perfect for these sugar cookie windows and doors.
Sift the confectioners' sugar into a mixing bowl. Add the butter and 1 1/2 tablespoons of milk. Beat the ingredients with an electric mixer until the mixture is smooth enough to spread or pipe on the cookies (you can add up to 1 tablespoon more of milk if necessary). For colored icings, divide the mixture into several portions and stir a few drops of food coloring into each.
Use a butter knife or spatula to spread the icing on the cooled cookies. If your child wants to pipe on the icing, show her how to use a pastry bag with a fine tip or spoon the icing into a small plastic bag and snip off a tiny piece of one corner. Makes about 1 cup of icing.