In a large mixing bowl, combine the melted butter, egg, and vanilla extract. Mix these ingredients using an electric mixer for 1-2 minutes until frothy.
– Gradually add the almond flour, sweetener, xanthan gum, and baking powder to the wet mixture. Mix until the ingredients are well combined and there are no lumps.
Bake in the oven for 10-15 minutes, until the middles are cooked and lightly golden. Remove the cookie cups from the oven and let them cool completely.