Makes about 2 1/2 cups
Place all ingredients in the bowl of an electric mixer and beat slowly until well blended, then beat at medium-high speed until icing forms stiff peaks, 6 minutes. If icing is not stiff enough, add more sugar; if it is too stiff, add more milk. Use immediately or place in a plastic container with a lid until ready to use. Allow icing to dry on cookies for at least 24 hours before packaging.