Preheat the oven to 350ºF and line a baking sheet with parchment paper.
Melt your coconut oil and set aside. Prepare the flax egg by adding 1 tbsp of flax meal to a small bowl with 3 tbsp of water. Let sit for 5- 10 minutes until a yolky consistency has formed.
Combine the dry ingredients in a bowl and whisk them together. I found using my kitchen aid worked the best to thoroughly combine the ingredients but you can still mix by hand it might just take a little longer and you may have you get your hands in there to get the right consistency.
Add the coconut oil and flax egg to the dry ingredients. Mix together. The consistency of the cookie dough should be crumbly, yet can be packed tightly into a ball. If you find it too crumbly and it breaks apart when rolling out, add an additional tablespoon of melted coconut oil at a time.
Form a large ball with all the dough.
Place a piece of parchment paper on the counter and place the dough on top of it. Place another piece of parchment paper on top of the dough and then using a rolling pin, roll the dough out. I wanted them to be on the thin side, roughly 1/8 of an inch in thickness. But they are a bit more delicate at this thickness until they are baked. If they are a little thicker than 1/8 that's fine, you'll just have more cookie in each oreo, and they may need to bake for 1 more minute.
Using a round cookie cutter ( 1 3/4" in diameter) or something that can act as a cookie-cutter, cut out small circles and place them on the lined baking sheet. These cookies don't spread so you can place them close to one another.
Gather up the loose cookie dough batter, and re-roll until you have 16-18 cookie rounds. Bake in the oven for 7-8 minutes. The cookies will still be slightly soft when they come out of the oven but they will harden as they cool. Let cool on the pan for 10 minutes, and then transfer them to a cooling rack to cool completely before icing them.