2 cup powdered sugar 1 tablespoon plus 1 1/2 teaspoons meringue powder* ¼ teaspoon cream of tartar ¼ cup warm water ½ teaspoon vanilla
To Store:
In an airtight container layer unassembled, unfrosted cookies between sheets of waxed paper Store at room temperature for up to 5 days or freeze for up to 3 months. Assemble and frost before serving.
*Note:
Meringue powder is a mixture of pasteurized egg whites, sugar, and edible gums. It is the secret ingredient to making Royal Icing dry quickly with a smooth, hard finish. Look for it in the baking aisle of large supermarkets or in the cake decorating department of hobby and crafts stores.
