Add the sugar, meringue powder, and 5 tablespoons water to a mixing bowl.
Beat until the icing is thick and of good spreading consistency, adding a few drops more water at a time, as needed.
If you mistakenly add too much water, simply add a bit more sugar and beat again.
Store in plastic zip-top bags or in covered bowls. (For best results, press plastic wrap directly on the surface of the icing.) Refrigerate until ready to use. Bring to room temperature before using. The icing will keep for a week or more when sealed in an airtight container or bag.