Preheat oven to 350°F (175°C) and grease or line a loaf pan.
In a large bowl, mash bananas until mostly smooth.
Add eggs, yogurt or cottage cheese, honey, oil, and vanilla extract. Mix until smooth and creamy.
In a separate bowl, combine flour, protein powder, baking powder, baking soda, and salt.
Add dry ingredients to wet ingredients and gently mix until just combined.
Fold in optional mix-ins if using.
Pour batter into prepared loaf pan and smooth the top.
Bake for 45 to 55 minutes until a toothpick inserted comes out with a few moist crumbs.
Cool in the pan for 15 minutes, then transfer to a rack to cool completely before slicing.