01 - Preheat the oven to 350°F and line a 12-cup muffin tin with paper liners or grease lightly with cooking spray.
02 - In a large bowl, mash the bananas until smooth. Whisk in eggs, Greek yogurt, honey, oil, and vanilla extract until fully incorporated.
03 - In a separate medium bowl, whisk together the whole wheat flour, baking soda, baking powder, cinnamon, and salt until well blended.
04 - Gradually add the dry ingredients to the banana mixture, stirring gently until just combined. Be careful not to overmix as this can result in dense muffins.
05 - Gently fold in the chopped nuts and optional dark chocolate chips until evenly distributed throughout the batter.
06 - Divide the batter evenly among the prepared muffin cups, filling each about 3/4 full to allow room for rising.
07 - Bake for 18-22 minutes, or until a toothpick inserted into the center of a muffin comes out clean with moist crumbs.
08 - Let the muffins cool in the pan for 5 minutes before transferring to a wire rack to cool completely.