Line baking sheets with parchment paper and set them aside.
In a large bowl, place the flour, xanthan gum, corn flour, baking soda, cinnamon, ginger, salt and granulated sugar, and whisk to combine well. Add the brown sugar, and whisk once more to combine, working out any lumps in the brown sugar.
Create a well in the center of the dry ingredients, and add the treacle, honey, vanilla, butter and egg, mixing to combine after each addition. The dough will be thick and smooth, and somewhat sticky to the touch.
Transfer the dough to a large sheet parchment paper, cover with another sheet of parchment and roll into a rectangle about ⅜-inch thick (more than ¼-inch, less than ½-inch). If you are concerned that the dough will be difficult to handle, place it in the refrigerator or freezer after you roll it out to allow it to firm up. Dip a gingerbread man cutter in gluten free flour or corn flour, and use it to cut out shapes from the cookie dough.
With each cut, jiggle the cutter back and forth to create a neat shape. Peel back the rest of the dough from around the cut-outs, and carefully peel off the men and place them, about 1½-inches apart, on the prepared baking sheets. Gather and re-roll scraps, and repeat the process until you have used all the dough.
Place in the center of the oven and bake until dry to the touch (about 12 - 15 minutes). Remove from the oven and allow to cool completely on the baking sheets
FOR THE ROYAL ICING:
Place powdered sugar in a medium bowl and set aside. In a small bowl, combine warm water, golden syrup or light corn syrup, and extract. Stir until syrup is dissolved.
Add syrup water to powdered sugar and stir until completely combined. Mixture will be thick. The consistency you're looking for is a slowly dripping icing that disappears into the bowl within about 12 seconds. Add water by drop if you think it's too thick. If it becomes too thin, add more powdered sugar by the teaspoon.
Add into a piping bag and decorate your gingerbread men.
Recipe by at https://laurasglutenfreekitchen.com/2020/12/gluten-free-gingerbread-men/