Combine almond flour, coconut flour, baking powder, and salt in a bowl.
Add cold unsalted butter and mix well using your hands or a food processor until crumbly.
Add erythritol, egg, and vanilla extract, then finish mixing the dough.
Divide the dough into 6 portions, place them on a pan, and shape them.
Bake in a 180°C oven for 15–20 minutes until golden brown.
Let cool to finish.