Preheat your oven to 350°F (175°C) and grease your muffin tin or line it with parchment paper liners.
In a large mixing bowl, whisk together the white whole-wheat flour, baking powder, baking soda, salt, and ground cinnamon. Set aside.
In another bowl, mash the ripe bananas until smooth. You should have about 1 ½ cups of mashed bananas.
To the mashed bananas, add the packed brown sugar, melted coconut oil, egg, Greek yogurt, and vanilla extract. Mix until well combined.
Gradually add the dry ingredients into the wet mixture, stirring gently until just combined. Be careful not to overmix; it’s okay if there are a few lumps!
Scoop the batter into the prepared muffin tin, filling each cup about 2/3 full. If desired, sprinkle a bit of turbinado sugar on top of each muffin for added crunch.
Place your muffin tin in the oven and bake for 18-22 minutes, or until a toothpick inserted into the center comes out clean.
Remove the muffins from the oven and let them cool in the tin for about 5 minutes before transferring them to a wire rack to cool completely. Enjoy warm or at room temperature!