This is your time to practice your best Grinch grin! 5. As your cookie cups cool, whip up a vibrant green frosting by stirring food coloring into white frosting. Then, pipe it into each cup and ...

3 cup powdered sugar, 2 tablespoon milk, 2 teaspoon vanilla extract Once the buttercream is mixed, add the green and yellow food coloring. Mix in until you have a Grinch Green colored frosting.