1. In a large bowl mix together confectioner's sugar and meringue powder.
2. Add in water and mix with hand mixer or stand mixer with whisk attachment. Check your consistency by lifting whisk (or with a spoon) and drizzle frosting down and the frosting should smooth out within 15-20 seconds. Flood consistency is when it icing self-levels. If frosting is too thick then add in more water. If frosting is too runny then add in more confectioner's sugar.
3. If coloring icing then use gel food colors.
4. Pipe or spread on to cookies. *If layering colors or designs, after 15-30 minutes icing will have formed a crust. Royal icing will completely set in 2-4 hours.