BEAT 3 Tbsp. meringue powder, 1/2 tsp cream of tartar and 6 Tbsp. warm water with electric hand mixer at high speed until blended. Slowly add 2 cups powdered sugar on low speed until blended; beat on high speed about 5 min. or until stiff peaks form.
COVER icing at all times to prevent hardening. To store several hours or overnight, place plastic wrap directly on surface of icing; refrigerate. Before using beat with mixer util stiff.