Preheat your oven to 350 degrees F.
In a small bowl, add your flaxseed and water and mix well to make the flax egg. Wait 8-10 minutes for the mixture to turn into a "gel".
In a large mixing bowl, whisk together the flour, baking soda, and salt, until there's no clumps.
In a smaller mixing bowl, cream together the coconut oil, brown sugar, vanilla extract, and almond milk. There may be some small clumps of coconut oil, however, try to whisk it until it's as smooth as possible.
Then, add your gelled flax egg to the coconut oil + brown sugar mixture. Mix until it's fully incorporated.
Then, add the wet ingredients into the dry ingredients. Mix until the dough is fully incorporated. Note that the dough will be very thick, and you may need to mix with your hands a little bit. Once the dough is even, do not keep mixing or kneading.
Then, mix in about 1 - 1 1/2 cups of your fillings of choice - chocolate chips, coconuts and pecans, or even walnuts and craisins!
On a baking sheet LINED WITH PARCHMENT PAPER, and using a cookie scoop, portion out your cookies into little balls. Note that they will flatten during baking. The final yield will be 16-18 cookies, so you will probably need to use two trays.
Cooking ONE tray at a time, bake your cookies in the oven for 14-15 minutes.
Let cookies cool before serving.
Enjoy!