Ingredients
1 1/2 sticks unsalted butter, room temperature
1/2 cup sugar
1/2 teaspoon kosher salt
1 teaspoon pure vanilla extract
1 2/3 cups plus 3 tablespoons gluten-free flour
Royal Icing, for decorating
Gold, silver, and white sprinkles or nonpareils, for decorating
Preparation
In the bowl of a mixer fitted with the paddle attachment, beat butter on medium-low speed until creamy, about 2 minutes. With mixer running, slowly sprinkle in sugar and salt; continue beating until fluffy, 2 minutes. Beat in vanilla. Reduce speed to low and add flour in two additions, beating just until incorporated. Finish mixing with a rubber spatula to avoid overworking dough. Turn dough out onto a piece of plastic wrap. Shape into a 5-inch square, wrap in plastic, and refrigerate until firm but still pliable, at least 2 hours and up to overnight.
Preheat oven to 325 degrees. Place dough between two sheets of lightly floured parchment and roll out 1/4 inch thick. Freeze 15 minutes. Using star cookie cutters (anywhere from 1- to 4-inch), cut out stars. Transfer to parchment-lined baking sheets, spaced 1 inch apart. Freeze 30 minutes. Bake, rotating pans halfway through, until pale golden brown around the edges, 15 to 20 minutes. Transfer sheets to wire racks and let cool completely.
Transfer royal icing to a pastry bag fitted with a coupler and a very narrow tip. Pipe icing onto cookies, either outlining or filling in with icing using a toothpick or small food-safe paintbrush. Decorate with sprinkles. Let stand until icing sets, at least 1 hour.
