MAKE THE ICING In a large bowl, using an electric mixer on medium speed, beat ¼ c. meringue powder and 5 tbsp. water until frothy and starting to stiffen, about 1 minute. Add 4 c. (460 g.) powdered sugar and beat on medium speed until thickened, 1 to 2 minutes. Add more water 1 tbsp. at a time until icing holds its shape without being too stiff to work with. Add a few drops of green liquid food coloring to icing.
DECORATE! Using a toothpick, swirl icing a few times to create a marbled effect. Working one at a time, dip tops of cookies into icing, then lift and allow excess to drip back into bowl. Continue to dip, swirling in more food coloring as needed, until cookie is coated.…
