Preheat the oven to 350 degrees F. Line a 9"x 9" baking sheet with parchment paper and grease the sides with cooking spray.
In a large mixing bowl, whisk together the oats, quinoa, sugar, baking powder, and hemp seeds.
In a separate bowl, mix the banana, nut butter, flax eggs, lemon juice and vanilla. Pour this mixture over the dry ingredients, mixing everything together until fully incorporated. The batter should be moist, but not runny. Fold in the blueberries
Transfer the batter into the prepared pan and smooth with a spatula.
Bake on the center rack for 25 - 35 minutes until the bars are golden brown and firm to the touch.
Remove and let cool completely in the pan, then remove and slice into squares (or rectangles). Store in an airtight container for 4 - 5 days.
I found that I enjoyed the texture of the bars best after being cooled on a wire rack overnight. Some of the added moisture from the blueberries was removed and they were even more hearty.