Prepare flax egg by mixing 1 tbsp of ground flaxseeds with 3 tbsp water
Combine oat flour, coconut flour, salt and baking soda in a medium bowl
In a large bowl, mix flax egg, butter, coconut sugar and vanilla
Slowly mix dry ingredients into wet ingredients
Roll into balls and place on a parchment lined cookie sheet
Flatten each with a spatula and Bake at 350 for 10 minutes