Prep your pan and oven: Heat the oven to 375°F (190°C). Line a 12-cup muffin pan with paper liners or grease lightly.
Mash the bananas: In a large bowl, mash the bananas with a fork until mostly smooth.
A few small lumps are fine.
Whisk the wet ingredients: Add the maple syrup or honey, oil, Greek yogurt, eggs, and vanilla. Whisk until well combined and creamy.
Combine dry ingredients: In a separate bowl, whisk the flour, baking soda, baking powder, salt, and cinnamon. If using lemon zest, stir it in here.
Bring the batter together: Add the dry mixture to the wet mixture.
Stir gently with a spatula until just combined. Do not overmix. The batter should be thick but scoopable.
Fold in blueberries: Gently fold in the blueberries, being careful not to crush them.
If using frozen berries, add them straight from the freezer.
Fill the muffin cups: Divide the batter evenly among the 12 cups. They’ll be almost full. Sprinkle the tops with turbinado sugar if you like a light crunch.
Bake: Bake for 16–20 minutes, or until the tops are set and golden and a toothpick comes out clean or with a few moist crumbs.
Cool: Let the muffins cool in the pan for 5 minutes, then transfer to a wire rack to finish cooling.
This helps them set and prevents soggy bottoms.
Enjoy: Serve warm or at room temperature. They’re great plain, with a smear of nut butter, or a dab of butter.