Makes about 24 (3-inch) cookies
2 1/2 cups plus 2 tablespoons (340 grams) unbleached all-purpose white flour
1/2 teaspoon baking powder
1/2 teaspoon salt
3/4 cup (1 1/2 sticks or 170 grams) unsalted butter, softened
1 cup plus 2 tablespoons (225 grams) granulated sugar
1 large egg
1 1/2 teaspoons vanilla extract
Whisk together dry ingredients in a medium bowl and set aside. In the bowl of a standing mixer fitted with the paddle attachment, combine butter and sugar and mix on medium speed for 1 to 2 minutes. Reduce speed to medium low and add egg and vanilla, mixing until combined, about 40 seconds. Reduce speed and gradually add the flour mixture, scraping down the sides of the bowl as needed. Beating just until dry ingredients are incorporated.
Preheat the oven to 350°F and line two baking trays with parchment paper. Working in three batches,roll dough out onto a floured surface to about ⅛ inch thickness and cut out with desired shapes. Gather up the scraps and press together into a disc. Reroll and cut out as above.
Bake the cookies until the edges begin to brown slightly, 9 to 15 minutes, depending on the size. Let the cookies rest on the baking sheet for 5 minutes, then transfer to a rack to cool completely before decorating.
Royal Icing with Egg Whites
Makes 2 cups
5 1/2 cups (562 grams) sifted confectioners’ sugar
7 tablespoons pasteurized egg whites
1/2 teaspoon lemon juice, optional
Combine the confectioners’ sugar and egg whites in the bowl of a standing mixer fitted with the paddle attachment. Beat on low speed until moistened and then increase speed to medium for 30 to 60 seconds. Add lemon juice, if using. With the mixer still on medium speed, beat until thick, soft peaks form, scraping down the sides of the bowl, 1 or 2 minutes.
Royal Icing with Dried Egg Whites
Makes 2 1/4 cups
3 tablespoons dried egg white powder
6 tablespoons warm water
4 1/2 cups minus 1 tablespoon (454 grams) sifted confectioners’ sugar
Combine the egg white powder and warm water in the bowl of a standing mixer fitted with the paddle attachment. Before placing the bowl under the paddle, use a hand whisk to break up as many large clumps of dried egg white powder as you can. (Don’t worry if all of them don’t dissolve.) Let sit for 2 minutes. Beat the mixture on medium-high speed until frothy, about 2 minutes. Reduce speed to low and gradually add the confectioners’ sugar, scraping the sides of the bowl as needed. Raise the speed to high and beat until smooth, about 2 minutes longer.