Preheat the oven to 350°F (175°C). Line an 8x8" baking pan with parchment paper or lightly grease it.
In a large mixing bowl, mash the bananas until smooth.
Add sunflower seed butter, melted coconut oil, egg, honey, and vanilla to the bananas. Mix well.
In a separate bowl, stir together the oats, protein powder, cocoa powder, flaxseed powder, chia seeds, baking soda, baking powder, and salt.
Add the dry ingredients to the wet mixture and stir until fully combined.
If the batter seems too loose, stir in 2–4 tbsp of flour to firm it up.
Fold in any optional add-ins like chocolate chips, nuts, or berries.
Spread the batter evenly into the prepared pan and smooth the top.
Bake for 22–26 minutes, or until the top is set and a toothpick inserted in the center comes out with a few moist crumbs.
Let the bars cool completely in the pan before slicing.
