In Instant Pot, add quinoa, rolled oats, cinnamon, milk and water and mix till combined. Place whole banana on top, do not stir again. Cover and pressure cook for 2 minutes and allow natural pressure release. (Stove top directions in notes)
While oat mixture is cooking, mix flax eggs (2tbsp flax + 4 tablespoon water) and set aside.
When pressure has naturally released from oat mixture, carefully remove lid. Stir in peanut butter, coconut sugar, flax eggs, vanilla extract and salt until fully combined and no large chunks of banana remain. Mixture will be thick.
If using chocolate chips, allow mixture to cool and then chill in the fridge until no completely cooled. (I usually leave mine in for a few hours) Oatie mixture needs to be cold when stirring in chocolate chips, or they will melt. (You can skip this step if the melted chocolate doesn't bother you!)
When mixture is cool, remove from fridge and fold in chocolate chips.
Dump oatie mixture on a parchment or silicone mat lined baking sheet and lightly flatten mixture with spatula or spoon.
Place another sheet of parchment top of mixture and use your hands to compress and smooth out the bars until flat to desired thickness, about ¾-1 inch thick. (The second parchment sheet limits the mess and make your bars a bit smoother.)
Remove top parchment sheet from bars and chill in freezer for 2-3 hours, until bars are no longer tacky to the touch. You want them to be hard enough that you can pick it up and transfer them to a cutting board without it breaking.
Remove from freezer, transfer to a large cutting board and cut into desired shapes. I usually shoot for small granola bar size, but you can do whatever you want!
Return to freezer until bars are very hard, then store in a bag or container in freezer until ready to use! Will keep in freezer for up to 6 months!