Preheat the Oven: Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
Prepare the Cookie Dough: In a mixing bowl, combine almond flour, cocoa powder, salt, xanthan gum, and baking soda. Mix well.
Add Wet Ingredients: In another bowl, cream together the butter and erythritol until light and fluffy. Add the egg and beat until well combined.
Combine Wet and Dry Ingredients: Gradually add the dry ingredients to the wet ingredients, mixing until a dough forms. If the dough is too sticky, you can refrigerate it for 30 minutes to firm up.
Shape the Cookies: Divide the dough into small portions and roll them into balls. Place them on the prepared baking sheet and press them down gently to flatten.
Bake: Bake the cookies in the preheated oven for 10-12 minutes, or until set. Remove from the oven and let them cool completely on a wire rack.
Prepare the Filling: In a bowl, beat together the butter, coconut oil, vanilla extract, salt, and powdered erythritol until smooth and creamy.
Assemble the Cookies: Once the cookies are cooled, spread a dollop of the vanilla cream filling onto the bottom of one cookie and sandwich it with another cookie.