Preheat oven to 375 F. Line a baking sheet with parchment paper.
In small bowl whisk together the ground flax and water. Set aside for 5 minutes until it thickens and gels.
Combine coconut oil and sugar together in a large bowl.
Stir in the vanilla and salt.
Add the flax egg, folding together with a spatula until combined.
Add in the cacao powder. Stir to combine with a spatula.
Add the flour a little at a time stirring in between until the dough forms.
Roll out the dough between two sheets of parchment paper to a thickness of ¼ inch.
Using a 2 inch round cookie cutter, cut out the cookies, and place on prepared baking sheet.
Bake for 8-10 minutes or until edges of the cookies are crisp around the edges, and the center is firm and set.
Allow to cool on the baking sheet for 10 minutes. Then transfer to a cooling rack to cool completely.