Preheat oven to 350°F. Line baking sheet with parchment paper.
Combine chia seeds with warm water in small bowl and let sit for 5 minutes. Take 1 ¼ cups oats and place in food processor and pulse until fine flour.
In large bowl, mix together oat flour, remaining oats, baking powder, baking soda, cinnamon and salt.
In a medium bowl, combine mashed bananas, peanut butter, maple syrup, coconut oil and vanilla extract. Stir in chia seed mixture.
Add wet ingredients to dry ingredients and mix until just combined. Fold in chocolate chips and walnuts.
Using an ice cream scoop or ¼ cup, scoop out batter onto baking sheet. Gently press flat with back of spatula. Bake for 20-22 minutes or until golden brown, rotating the pan halfway through. When done, remove from oven and let cook on sheet for 5 minutes before transferring to cooling rack.
Let the chia seeds sit in water for at least 5 minutes so it soaks up the water and creates an egg-like consistency.
The riper the banana the sweeter it is which makes for great vegan banana muffins. You want a banana that has black/brown spots on the peel.
While you can substitute oats, I suggest using old-fashioned oats so you get a heartier breakfast cookie.
If you're looking for some substitutions for ingredients, you can use vegetable oil instead of coconut oil and honey instead of maple syrup.
Use half whole wheat and half all-purpose flour to get more nutrition but not make them too dense.
Don't skip out on roasting the walnuts. By roasting them they will stay crispy in the batter and bring out the flavor.
Use ice cream scoop to be consistent with the size of the cookies.