You don't have to be gluten-free to enjoy these Christmas sugar cookies. We've transformed the easy dough into stars gilded with royal icing and sprinkles, but you can shape and decorate any way you like.
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.
You can use any gluten-free flour for this recipe. Our test kitchen's picks: Cup4Cup or Bob's Red Mill.