An easy-to-make royal icing is the basis for our cookie-decorating techniques. Because royal icing can harden quickly, decorate the cookies while the icing is still soft and moist.

Royal Icing:

3 egg whites, at room temperature
4 1/2 cups confectioners' sugar, sifted
1/2 tsp. cream of tartar
Pinch of salt

In the bowl of an electric mixer, beat the egg whites on medium-high speed until frothy. Add the sugar, cream of tartar and salt and continue beating until stiff peaks form, 7 to 8 minutes. Cover tightly with plastic wrap and store at room temperature for 4 to 6 hours. Makes 5 to 6 cups.

What You'll Need for Decorating:

• Royal icing, some of regular consistency and some thinned (see Flowing, below)
• Food-coloring paste
• Pastry bags, with a small round tip (#2 size is good)
• Colored sugars, glitters and confetti
• Icing pens

Tips for Cutting and Baking Cookies:

To yield the greatest number of cookies, begin cutting the rolled cookie dough from the edge.

When baking successive batches of cookies with one baking sheet, let the sheet cool to room temperature before placing more cookie dough on it. On a warm sheet, the dough would immediately begin to melt, distorting the cookies' shapes, thinning their edges and altering their texture.

After removing a cookie sheet from the oven, immediately loosen the cookies using a thin metal spatula so they won't stick. Then set the sheet on a wire rack and cool for 5 minutes. After the cookies have cooled and their shape has set, transfer them to a wire rack to cool completely before icing and decorating.

Tinting
To make icing in several colors, divide the plain icing among small bowls. Then add food-coloring paste a drop at a time, stirring with a small spoon, until it achieves the desired hue. Keep the icing tightly covered with plastic wrap while not in use.

Flowing
Before flowing icing from a pastry bag over the top of a cookie, make a border of royal icing around the area to be filled. Then thin the icing that will be flowed to ensure it spreads smoothly: Transfer a portion of the thick icing to a bowl and stir in warm water, 1 tsp. at a time, until a drop of the icing slowly spreads outward without being watery.

The thinned icing is best applied using a pastry bag fitted with a #2 tip. To fill in the outlined area, work from the perimeter toward the center, letting the icing flow while gently maneuvering it with the tip. If tiny air bubbles appear on the surface, this means that too much air was whipped into the icing. Simply prick the bubbles with a straight pin while the icing is still moist.

Flocking
While the thinned royal icing is still wet, sprinkle it with edible colored sugars, glitter or confetti. (These will also adhere to a border of thick icing if it is still moist.) Let the icing dry completely before shaking off the excess decorations.

Borders and Lines
Royal icing has the ideal consistency for creating borders, lines and calligraphy. It can be easily applied using a pastry bag fitted with a small pointed decorating tip, or you can use colored icing pens.