Preheat oven to 375 degrees.
Beat butter and sugar in an electric mixer set on medium for about 30 seconds. Beat in egg and vanilla extract until combined.
In a separate bowl, combine gluten-free flour, xanthan gum, baking powder and salt.
Add the flour mixture to the butter mixture, beating on low speed until combined.
Pack the dough into a cookie press. If it’s too sticky, put in the refrigerator for 30 minutes to harden.
Place the face of the press firmly down on an ungreased cookie sheet and press out cookie, a single press for each cookie. Space cookies about 1 inch apart. Decorate with colored sugar, sprinkles, etc.
Bake for 8-10 minutes on center rack in preheated oven until cookie edges are very lightly brown and edges are firm.
Cool cookies on the cookie sheet for a couple minutes before transferring to a wire rack to cool completely.
Store cookies in airtight container for up to 7 days. You can freeze them too!