This simple icing is all you need to decorate cut-out cookies made from U-bake Vanilla Shortbread dough. Apply the icing with the back of a spoon and add a dusting of colored sugar. For more detailed designs, pipe on icing with a decorating kit, plastic bottle or a zip-top bag.
Makes 3 1/2 cups icing
2 large egg whites, plus extra for thinning icing
2 tablespoons fresh lemon juice
4 cups confectioners sugar, sifted
Liquid or gel food coloring (find gels at kitchen or decorating shops)
In a medium mixing bowl or electric stand mixer fitted with whisk attachment, lightly whisk the egg whites and lemon juice. Add 3 1/2 cups sifted confectioners sugar and beat well until smooth and glossy. It should pause slightly before it streams off the tip of the beater. Add more egg white or lemon juice if too thick, more sugar if too thin.
Make-ahead note: Icing can be stored in an airtight container in the refrigerator for up to 3 days. Whisk before pouring into small bowls to add color.
Add color, fill pastry bags.
Divide icing among small bowls and stir in food coloring a few drops at a time until desired color is reached.
“Flooding” is a technique used to cover a cookie completely with royal icing. Here’s how to do it:
Transfer about 1/2 cup of royal icing to a resealable plastic bag and snip a small corner (or use a pastry sleeve fitted with No. 4 tip). Use this icing to pipe a thin border around the edge of each cookie. Thin additional icing (same color) and transfer to bags. Snip a corner and pipe a generous amount inside the border of each cookie. Using a small offset spatula or the back of a spoon, spread the icing to cover the cookie.
For a sparkling effect, apply colored sugar to wet icing then tip the cookie to remove excess sugar. You can use coarser decorating sugar as well; apply and let the cookies sit for about 15 minutes before removing excess sugar. Let dry before adding piped borders, stripes or other decorations with additional royal icing.
For a marbleized look, flood cookie surface. Add stripes or dots in a second color, then drag a toothpick through.
How to test icing: Before you fill a pastry bag, test icing with a spoon; for detail work, it should pause slightly before it streams off the tip of a spoon. For covering the whole cookie, you’ll want it slightly thinner, which will cause it to stream off the spoon immediately.
For more tips and ideas, watch our Holiday Cookie Decorating Video.