Preheat the oven to 350° and line a cookie sheet with parchment paper.
In a large bowl, combine the almond flour, coconut flour, coconut sugar, salt and baking soda. Stir to combine. Add in the coconut oil and flax egg and mix until dough is formed.
Divide the dough into 10 balls, about 1 tablespoon each and roll in between palms to make smooth. Take one ball and press it flat and place half a truffle in the center. Wrap the cookie dough around it until it's completlely covered and roll until smooth again. Place on the cookie sheet and repeat until they are all stuffed.
Spread the cookies evenly out on the cookie sheet, about 2 inches apart and bake 10-11 minutes. Enjoy warm while the inside chocolate is gooey. Store any leftovers covered in the fridge.