Preheat the oven to 350 degrees Fahrenheit. Line a large cookie sheet with parchment paper.
In a large mixing bowl, cream together the coconut sugar, almond butter, coconut oil, ground flaxseed, and vanilla for 1 minute.
In a separate mixing bowl, whisk together the dry ingredients (oat flour, coconut flour, baking soda, and salt).
With the mixer off, add the oat flour mixture to the almond butter mixture and beat until just combined and the dough pulls together into large mounds as it moves around the mixing bowl. (At first, it will appear crumbly, but just keep beating until it pulls together.) Do not over mix. The dough should be a bit oily to the touch.
Scoop out and roll a 1 ½ tablespoon mound of the dough into a ball. You want the ball of dough to be as tightly compacted as possible. Place on the parchment-lined pan, and use a fork to very gently press one way and then the other to create a crisscross pattern. If any bits or pieces crumble off the edges, simply use your fingers to press and compact them back into the cookie.
Repeat with the remaining dough. You should have about 14 cookies (these cookies don't spread much while baking, so leaving just an inch or two of space between each is fine).
Bake for 10 to 14 minutes, or until the edges begin to turn a rich golden brown shade.
Cool completely on the pan before moving or enjoying. (If you attempt to move or enjoy them before they've cooled, you'll end up with a crumbly cookie mess.)
I love these cookies chilled straight from the fridge, so I store them in the refrigerator (they'll keep for up to two weeks there or up to one month in the freezer).