Preheat your oven to 350 F and line a baking sheet with parchment paper.
In a large bowl, beat the softened butter and erythritol together until fluffy. Add the egg and vanilla extract, mixing until combined.
Stir in the almond flour, baking powder, cream of tartar, and sea salt. Mix until a soft dough forms. Refrigerate the dough for 15 minutes to make it easier to handle.
In a small bowl, combine the 2 tablespoons erythritol and cinnamon for rolling.
Scoop tablespoon-sized portions of dough, roll into balls, then roll each ball generously in the cinnamon mixture. Place on the prepared baking sheet 2 inches apart and flatten slightly with your palm.
Bake for 10 to 12 minutes until the edges are lightly golden but the centers still look soft. Let cool on the baking sheet for 10 minutes before moving to a wire rack.
