In a large mixing bowl, whisk together the powdered sugar and meringue powder to ensure even distribution.

Slowly add warm water to the dry mixture, starting with 5 tablespoons. Mix on low speed until combined, then increase to medium speed.

Continue mixing until the icing reaches a smooth and glossy consistency.

If it's too thick, add an additional tablespoon of water until desired texture is achieved.

If desired, mix in vanilla extract at this stage.

Check the icing by lifting the mixer; it should form stiff peaks.

If you plan to use different colors, divide the icing into separate bowls and add food coloring a few drops at a time.

Fill piping bags with the colored icing and twist the top of the bag to prevent spills.

Use the icing to decorate your cooled sugar cookies and let them dry completely.