Combine the confectioners’ sugar and meringue powder in a large mixing bowl.
Add the warm water, 1 tablespoon at a time, while mixing with a hand mixer on low speed.
Add the vanilla extract and continue mixing on low until the icing becomes shiny.
Keep mixing on low speed for 5–7 minutes until the icing reaches the right consistency.
Use a toothpick to add food coloring to the icing and mix until you achieve the desired color.
Transfer the colored royal icing to a piping bag and tie it off. Make sure the cookies are completely cool before piping the icing on top!
Notes
For each color of icing, you need 2 different consistencies of icing. For a thinner consistency, add more water to the mixture. Thinner icings are used for flooding, and thicker icing is used for borders and edges.
For thicker icing, cut the piping bag very thinly, around a 1/16 of and inch. For thinner icings, cut ⅛ of an inch. If this is too small, you can always cut more bag.
After decorating cookies, dry the icing with a craft heat gun 10 inches away, so the flooded icing does not cave on itself.
I like to let my cookies air dry in a cool space for 2 days, then they’re ready for packaging.