Ingredients

2 pounds confectioners' sugar, sifted 

1/2 cup plus 2 tablespoons meringue powder 

Scant 1 cup water, plus more if needed 

Preparation

With an electric mixer on low speed, beat ingredients until fluffy, 7 to 8 minutes. Use immediately, or transfer to an airtight container (royal icing hardens quickly when exposed to air) and refrigerate up to 1 week. Stir well with a flexible spatula before using.

Thin icing as needed by stirring in additional water, one teaspoon at a time. For piping designs, add just enough water that icing is no longer stiff; for floodwork, add water until icing is the consistency of honey.