Preheat oven to 350° F.
In a small bowl whisk together ground flaxseed with water to make your flax egg and set aside.
In a large bowl, combine the dry ingredients -- oats, oat flour, sugar, baking powder, baking soda and salt.
In another bowl combine the wet ingredients -- flaxseed egg, maple syrup, coconut oil and vanilla.
Add the wet ingredients into the bowl with the dry ingredients and stir to combine. Gently stir in the chopped dates and walnuts.
Place dough in the fridge to setup for 30 minutes (do not skip this step).
Drop rounded tablespoons onto a baking sheet lined with parchment paper or a baking stone. Make sure you space the cookies out because they tend to spread a bit. Bake for 10-12 minutes or until cookies are golden brown.
Allow cookies to cool on the pan for 1-2 minutes then gently move to a wire rack and cool completely before eating or transferring to a storage container for later. Store cookies in the fridge for up to 5 days or freezer for up to 3 months.