Preheat your oven to 350°F (175°C) and grease a loaf pan with coconut oil or line it with parchment paper.
In a large bowl, combine the mashed bananas, eggs, melted coconut oil, unsweetened applesauce, Greek yogurt, and vanilla extract. Mix well until smooth.
In a separate bowl, whisk together the all-purpose flour, protein powder, baking powder, baking soda, ground cinnamon, and salt.
Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Be careful not to overmix.
Pour the batter into the prepared loaf pan, spreading it evenly. If desired, sprinkle the optional toppings on top.
Bake for approximately 45-55 minutes, or until a toothpick inserted into the center comes out clean.
Remove the banana bread from the oven and allow it to cool in the pan for about 10 minutes. Then transfer it to a wire rack to cool completely before slicing.
Enjoy your high-protein banana bread!