Preheat oven to 325 degrees F. Lightly grease a baking sheet and set aside.

Pulse walnuts and pecans in a food processor and pulse until finely ground (you may need to alternate in batches depending on how large your food processor is). You don't want it to be butter, but it should resemble fine crumbs.

Transfer nuts to a large bowl and place oats in a food processor and pulse until a fine flour forms.

Place the oats into the bowl with the nuts along with the baking powder, salt and cornstarch.

In a separate bowl, whisk together the ground flax seeds and water and let sit until gelled, about 5 minutes.

Add the oil, maple syrup, and vanilla extract to the flax seed bowl and whisk together.

Stir the wet flax-oil mixture into the nut and oat mixture and stir to combine. Gently fold in chocolate.

Using a 2 tablespoon cookie scoop (or measuring cup), scoop out dough and gently press together and flatten with your hands. They might crumble a bit but should form into a cookie once pressed together.

Place on lightly greased baking sheet and cook for 15 minutes until golden brown, check after 10 minutes.

Let cool completely before serving.