Watch the video tutorial so you get an idea of what the final consistency should be.

In a large bowl using a handheld or stand mixer fitted with a whisk attachment, mix the confectioners’ sugar and meringue powder.

Add the water and a flavoring (if using), and whip on high speed for 1.5–2 minutes. When lifting the whisk up off the icing, the icing should drizzle down and smooth out within 5–10 seconds. If it’s too thick, whip in more water, 1 Tablespoon at a time. I usually need 10 Tablespoons, but on particularly dry days, I use up to 12–14 Tablespoons. Keep in mind that the longer you whip the royal icing, the thicker it becomes. If your royal icing is too thin, just keep whipping it to introduce more air, or you can add more sifted confectioners’ sugar.

If you’d like to tint the icing, divide it into separate bowls for each color, or tint the entire batch one color. A little gel food coloring goes a long way, so use a toothpick to dot the gel into the icing. Stir it in and then add more to deepen the color if desired. Keep in mind that the more you stir, the thicker the icing becomes. If needed, stir in a few drops of water to maintain the target consistency.

When applied to cookies or confections in a thin layer, icing completely dries in about 2 hours at room temperature. If the icing consistency is too thin and runny, it will take longer to dry. If the icing is applied very thickly, it will also take longer to dry. If you’re layering royal icing onto cookies for specific designs and need it to set quickly, place cookies in the refrigerator to help speed up the setting. See blog post above for make-ahead and freezing instructions.