Preheat oven to 350 degrees and line loaf pan with parchment paper.
Combine bananas, eggs, and egg whites in blender.
Pulse in baking powder, cinnamon, almond flour, and protein powder until well combined, scraping sides of blender with spatula as needed.
Pour mixture into loaf pan and bake for 50-55 minutes, until toothpick inserted in center comes out clean.
Allow loaf to cool completely before slicing with sharp knife.