In a large mixing bowl combine egg, melted and cooled coconut oil, coconut sugar, and vanilla extract. Whisk into an even mixture

In a separate mixing bowl combine almond flour, coconut flour, baking soda and salt

Fold dry ingredients into wet and mix until evenly combined

Chop chocolate bar into small chunks and fold chocolate into dough

Place dough in the fridge to chill for 30 minutes

Remove douhg from the fridge and turn out on a piece of parchment paper

Roll the dough into a tight ball and then into a log - be sure to roll the log tight and without any gaps. If there are gap the cookies will crumble when sliced

Wrap the log in parchment and place in the fridge or in plastic wrap and then parchment if you are placing in the freezer for later

Allow the dough to chill in the refrigerator for at least 4 hours

Preheat oven to 350F and line a baking sheet with parchment paper

Take dough from fridge and immediately slice into 1/2" thick rounds. If using dough from frozen, unwrap and allow to thaw for 1 hour before slicing

Lay on the baking sheet, sprinkle with flakey sea salt and bake at 350F for 14 minutes

Remove from the oven and cool on the baking sheet for a few minutes before transferring to a cooling rack