In a medium bowl, whisk together the gluten-free flour blend, xanthan gum (if using), ground ginger, ground cinnamon, ground cloves, ground nutmeg, kosher salt, and baking powder. Set aside.
In a large mixing bowl, cream together the softened butter and brown sugar for 2-3 minutes. Scrape down the sides of the bowl as needed.
Add the molasses, egg and vanilla extract and mix an additional 2 minutes, until combined.
Slowly add the flour mixture, mixing in between each addition, until no more streaks of flour remain.
Turn the dough out onto parchment paper or plastic wrap and pat into a disk. Refrigerate for at least 3 hours until chilled.
Once chilled, preheat the oven to 350F and line two baking sheets with parchment paper or silicone baking mats.
Dust your surface and rolling pin with additional gluten-free flour or confectioners’ sugar. Roll out the cookie dough to ¼ inch thickness and cut with desired cookie cutters.
Place the cookie dough shapes onto the prepared baking pans, leaving about 1-2 inches in between each cookie. Keep remaining dough in the refrigerator or freezer if you are baking in batches.
Bake at 350F for 9-11 minutes, until the cookies are fragrant and the center of the cookie no longer looks shiny.
Let sit on the baking sheet for 5 minutes before transferring to a cooling rack to finish cooling.
Once cooled, decorate cookies as desired with royal icing or your favorite icing recipe. Let the decorations harden completely before serving.