1Heat oven to 375°F. In medium bowl, stir cookie ingredients until soft dough forms. Refrigerate 1 hour.
2On generously floured surface, roll dough 1/8 inch thick. Cut with 3-inch star-shaped cookie cutter. Reroll and cut remaining dough. On ungreased cookie sheets, place cutouts 1 inch apart.
3Bake 7 to 9 minutes or until edges are set. Cool 1 minute; remove from cookie sheets. Cool completely, about 15 minutes.
4In small bowl, stir 2 tablespoons of the milk, the orange liqueur and powdered sugar until smooth. Stir in orange peel. Add additional milk 1 teaspoon at a time to desired consistency. Spread over cookies, sprinkle with edible glitter.