Combine almond flour and coconut flour in a bowl and mix together.
Add baking powder, salt, and erythritol; mix well.
Add eggs, milk, and melted butter, then mix in one direction.
Once the dough comes together, shape it into your desired size.
Line a baking sheet with parchment paper and place the dough on it.
Bake in a preheated oven at 180°C (356°F) for 20 minutes.