Beat together softened butter and sweetener for 2 minutes.
Add egg and vanilla. Beat to combine.
Add the almond flour, salt and Xantan gum. Mix to combine.
Stir in the chocolate chips.
Wrap the dough in plastic wrap and refrigerate for at least 30 minutes or up to 2 days.
Preheat oven to 350F.
Line a baking sheet with parchment paper or Silpat.
Scoop out about 1 1/2 tablespoon of the dough for each cookie. Roll into balls.
Place on the baking sheet, leaving at least 1 inch between each cookie. Slightly flatten each ball.
Bake for 12-14 minutes, until the edges are golden. Cool cookies on the baking sheet for 10 minutes, then transfer to a cooling rack.
Store cookies in an air-tight container at room temperature for 5 days.