To a medium pot on high heat, add the oats, milk, cinnamon, pumpkin pie spice and one of the bananas. Bring to a boil, then reduce to a simmer for 8 minutes, stirring on occasion. Note: the milk can boil over if too hot, so keep close and reduce the heat if needed.
Add the other banana and flaxseeds, cooking for another 2-5 minutes. Note: the porridge will thicken as the flaxseeds gel. The first banana should be almost completely dissolved in the oatmeal, making it creamy, while the second banana provides the oatmeal with some texture and naturally sweetens.
At the end, add the vanilla extract and remove from the heat. Add more milk or water if you like it thinner, or cook for another couple minutes longer if you like it thicker. Add toppings and enjoy!
