Preheat and prep the pan. Heat your oven to 350°F (175°C). Line a 9x5-inch loaf pan with parchment paper and lightly grease the sides. This makes the loaf easy to lift out.

Mash the bananas. In a large bowl, mash the ripe bananas until mostly smooth with a few small lumps. You’ll get better flavor and sweetness from very spotty bananas.

Whisk the wet ingredients. Add the eggs, Greek yogurt, oil, maple syrup, and vanilla to the bananas. Whisk until the mixture is smooth and well combined.

Mix the dry ingredients. In a separate bowl, whisk the white whole wheat flour, oat flour, protein powder, baking soda, baking powder, salt, and cinnamon. Stir until everything looks evenly mixed.

Combine gently. Add the dry mixture to the wet mixture. Use a spatula to fold until just combined. Do not overmix, or the bread can turn dense or rubbery.

Add extras. Fold in nuts, chocolate chips, or seeds if using. Spread the batter into the prepared loaf pan and smooth the top.

Bake. Bake for 45–55 minutes. The top should be golden and a toothpick inserted in the center should come out mostly clean, with a few moist crumbs.

Cool properly. Let the loaf cool in the pan for 10 minutes. Lift it out using the parchment and transfer to a wire rack to cool completely before slicing. This helps set the crumb and prevents a gummy texture.

Slice and serve. Use a sharp serrated knife to cut clean slices. Enjoy plain, with a smear of peanut butter, or a little butter.