Royal Icing

Steps

1. Whisk the powdered sugar and meringue powder together in a stand mixer bowl. Add the 6 tablespoons warm water and the vanilla.
2. Using the paddle, mix on low speed just until no dry sugar remains, then beat on medium-low for 5 to 7 minutes. It is ready when it is thick and bright white and a lifted beater leaves a stiff peak. A hand mixer works too but may take a few minutes longer.
3. Spoon the icing into small bowls, one for each color. Royal icing starts to harden within minutes in open air, so keep every bowl you are not working with under a damp towel or plastic wrap.
4. Tint each bowl with gel coloring, adding it in tiny amounts and stirring until the color is even.
5. For outlines and lettering, set aside part of each color and stir in water a few drops at a time until it is about as thick as toothpaste and holds a line when piped.
6. For flooding the tops, thin the rest of each color with a little more water, until a ribbon drizzled over the surface sinks back in about 15 seconds.
7. Use a piping bag and a small round tip for each color, or cut a tiny hole in the corner of a zip-top bag. Outline each cooled cookie, then fill the center and nudge the icing into the corners with a toothpick.
8. Let the cookies dry uncovered at room temperature until the icing is hard, at least 6 hours or overnight, before stacking or packing.

Good to know

• Leftover icing keeps for up to 3 days at room temperature in an airtight container with plastic wrap pressed on the surface. Stir or beat it briefly before using, since it separates as it sits.
• Keep the bowl and beaters free of butter or grease, which can stop the icing from thickening and drying hard.
• Regular vanilla gives the icing a soft ivory tint, so use clear vanilla when you want the whitest white. Try 1/2 teaspoon almond extract or 1 teaspoon fresh lemon juice in place of the vanilla.
• Deep reds and greens darken as they dry, so mix them a shade lighter than you want.