Make the flax egg by mixing the filtered water with one tablespoon of ground flax egg. Gently mix the two ingredients together with a fork in a small bowl and set it aside to thicken.
Add the room-temperature soft butter and coconut sugar to a large mixing bowl. Use an electric mixture to beat the ingredients until they are nice and creamy.
Next, add the maple syrup, flax egg, and vanilla extract. Mix together for about 20 seconds.
Now it is time to add the dry ingredients to the bowl of wet ingredients. Add the oat flour, baking soda, baking powder, and salt. Mix everything together until a thick cookie dough forms.
Chop up your chocolate bar and add that to the cookie dough mixture. Use a spatula to gently fold in the chocolate pieces until they are evenly incorporated into the dough.
This is the hardest part. Cover the large bowl with plastic wrap and place the dough in the fridge for 24 hours to chill. Don't skip this step. It makes for the perfect chocolate chip cookie.
You made it! Now, let's bake these vegan cookies. Preheat the oven to 350 degrees Fahrenheit and line a baking tray with a silicone mat or parchment paper.
Remove the chilled cookie dough from the fridge. Grab a cookie scoop and scoop out 11-13 evenly-sized cookies and place them on the cookie sheet. You will want to cook them in two batches so you have room to spread them apart on the cookie sheet. Do not flatten the cookies as they will spread while baking. Also, do not put two trays in the oven at the same time. Cook one half at a time on one cookie sheet.
Before placing the cookies in the oven, add a few extra chocolate chunks to the tops of the cookies. Promise me, the cookies will turn out beautiful if you do this.
Bake the cookies for roughly 12 minutes. *Baking time depends on your oven, location, etc. You may need to add another minute or cook a minute less. The cookies will look and feel underdone when you pull them out of the oven but don't worry, once they cool, they will harden up a bit.
Remove the cookies from the oven, and carefully tap the tray a few times on the counter to finish off the texture of the cookie. Allow the cookies to cool on the baking sheet for about 5 minutes and then transfer them to a cooling rack.