Mix almond flour, coconut flour, baking powder, salt, and erythritol in a bowl.
Add eggs, coconut oil, and vanilla extract, then knead into a dough.
Shape the dough into a flat circle, spread a bit of butter on top, cut into triangles, and place on a baking tray.
Bake in a preheated oven at 180°C (356°F) for 20–25 minutes.
Let cool before serving.