In a bowl combine coconut flour, almond flour and baking powder. Stir very well to blend and set aside.

In a large mixing bowl whisk the melted butter and the erythritol for about a minute. Add the eggs and vanilla and whisk again for a few seconds, until smooth.

Gradually add the dry ingredients. Mix gently with a wooden spoon until absorbed in the dough.

Add also the chocolate chips/ crushed chocolate. Mix to distribute evenly into the dough.

Wrap the bowl with cling film and place it in the fridge for about an hour.

Preheat the oven to 350º F/ 180º C. Line two large baking tins with parchment paper.

Make small balls with your hand: about the size of a large walnut. Flatten them to about ¼ inch or 0,6 cm.

Bake for 5 minutes just on the top and then switch to normal baking (bottom and top, no fan) for 10 more minutes. The cookies are ready when the the tops start becoming just slightly golden and the edges are already golden brown.

Let cool for 5 minutes on the pan and then move to a wire rack to cool completely.