Preheat your oven to 325°F. Line rimmed baking sheets with unbleached parchment paper and set them aside.

In a large bowl, place the flour, xanthan gum, cornstarch, confectioners’ sugar, salt, and baking soda, and whisk to combine well.

Create a well in the center of the dry ingredients and add the butter, egg, and vanilla, and mix until all the dry ingredients are moistened. It helps to press down with the back of a mixing spoon, rather than just turning the mixture over with the bowl of the spoon.

With clean hands, knead the dough together until it’s cohesive.

Place the dough on a lightly floured surface, and roll it about ¼-inch thick, sprinkling lightly with flour as you roll to prevent sticking. Turn and rotate the dough often.

Place the rolled out dough, still on the rolling surface or another flat surface, in the refrigerator to chill for about 10 minutes or until firm.

Remove the rolled out dough from the refrigerator and, using small animal-shaped (or any-shaped) cookie cutters, cut out shapes.

Place the shapes on the prepared baking sheet about 1-inch apart. They won’t spread much during baking.

Place the baking sheets, one at a time, in the center of the preheated oven.

Bake for 8 to 10 minutes, or until the cookies are set and just beginning to brown slightly around the edges. Do not overbake.

Allow the cookies to cool completely on the baking sheet, as they’re very fragile until cool.

Make the (optional) frosting recipe (or the royal icing at the link in the ingredients list).

Place the confectioners’ sugar in a medium-size bowl and whisk to loosen.

Add the light corn syrup, 1 tablespoon lukewarm water, and a bit of gel food coloring. Mix until smooth.

The mixture will be very thick. Add more water by the drop, mixing to combine after each addition, until the frosting falls off the utensil slowly in about a ¼-inch thick ribbon.

Dip one side of each cooled cookie in the frosting, coating it completely.

Invert the cookie as you remove it from the frosting, and then replace it on the cooled baking sheet.

Sprinkle immediately with nonpareils, if using. Repeat with the remaining cookies, or as many as you like.

The frosting will be completely set after 12 hours if you used royal icing, and after 24 hours if you used the frosting.

These can be stored in a sealed glass container at room temperature and they’re retain their texture for at least 5 days.

For longer storage, seal tightly in a freezer-safe container, and freeze for up to 2 months. Defrost at room temperature.