with Royal Icing
In large mixing bowl, combine sugar, butter, shortening, eggs and 1½ teaspoons vanilla; using an electric mixer on medium speed, beat until light and fluffy.
Reduce mixer to low; add flour, baking powder and salt, mixing until well combined, scraping bowl often. Refrigerate, covered, 1 hour or until ready to use.
Divide dough into fourths; work with one-fourth at a time keeping remaining dough refrigerated. Roll dough ⅛-inch thick on lightly floured work surface, cut with favorite cookie cutters.
Place cutouts onto ungreased baking sheet. Bake in a preheated 400°F oven 6-8 minutes or until set but not browned. Remove to wire rack to cool completely.
5. Place egg whites in a large mixing bowl; using an electric mixer on high speed, beat until frothy. Slowly add in powdered sugar, remaining vanilla and food coloring, if desired; beat until thick and soft peaks form. Frost cookies; let stand until icing hardens.