Preheat the oven to 350° F (176° C). Line a baking sheet with a silicon mat or parchment paper.
Add the butter and sugar to a mixing bowl. Beat until fluffy, about 3 minutes.
Whisk the egg in a small bowl and reserve 1 tbsp to brush on the tops of the cookies. Add the remaining egg, and the rest of the cookie ingredients to the bowl and mix together until well combined.
Scoop the batter into 12 balls and arrange evenly on the baking sheet. Flatten the balls with your hands or with the bottom of a glass so they are about 1/4" thick circles. Brush the tops with egg.
Bake for 15-20 minutes, until firm and golden.
Meanwhile, mix the glaze ingredients in a bowl. Beat until fluffy, about 3-5 minutes.
Once the cookies have cooled completely, spread the glaze on the tops and serve.
Notes
The xanthan gum is optional, but it gives the cookies a bit more chew, so they are less crumbly.
The frosting is also optional. It can also be served on the side.
The addition of coconut flour gives these cookies a firmer texture, which I prefer. If you don't have coconut flour or don't wish to mix them, you can use 1 1/2 cups of almond flour and omit the coconut flour. You cannot, however omit the almond flour.
The information shown is an estimate provided by an online nutrition calculator. It should not be considered a substitute for a professional nutritionist’s advice.