1 cup powdered sugar
2 teaspoons meringue powder
1 tablespoon water
Green food coloring
Yellow food coloring
Sealable plastic bag
Step 1: Make the Royal Icing
Scoop most of the icing into another bowl, leaving a few tablespoons. Add a few drops of the green food coloring to the majority of the royal icing and mix. Add a couple of drops of yellow food coloring to make it a brighter green, and mix.
Step 2: Prepare the Frosting Bag
Seal the bag, and snip off one of the corners.
Step 3: Frost the Tops
Use a toothpick to help nudge the color into its proper place.