01 - Preheat the oven to 350°F. Lightly grease a 9x9 inch baking dish with cooking spray or a small amount of oil.
02 - In a large bowl, whisk together the mashed bananas, eggs, Greek yogurt, honey, almond milk, and vanilla extract until completely smooth and well incorporated.
03 - In a separate medium bowl, combine the rolled oats, protein powder, baking powder, cinnamon, and salt. Stir to ensure even distribution.
04 - Add the dry ingredients to the wet mixture. Stir gently with a spatula until just combined, being careful not to overmix.
05 - Gently fold in the blueberries until evenly distributed throughout the batter.
06 - Pour the batter into the prepared baking dish, spreading evenly. Sprinkle with chopped nuts and chia seeds if using.
07 - Bake for 35 to 40 minutes, or until the top is golden brown and a toothpick inserted in the center comes out mostly clean.
08 - Let the breakfast bake cool for 10 minutes before slicing into squares. Serve warm or at room temperature.