Preheat the oven to 180°C (356°F).
Mix almond flour and coconut flour together.
Add erythritol and salt, and mix well.
Add eggs and butter, then knead into dough.
Fold in dark chocolate chips evenly.
Shape the dough into balls and place them on parchment paper.
Bake in the oven at 180°C (356°F) for 15 minutes.
Let them cool before serving.