In a large mixing bowl, whisk together flour, sugar, baking soda, baking powder, salt, and cinnamon.
In a small bowl, mash the bananas until smooth (you should have about 1 cup).
Add mashed bananas to large bowl, then crack eggs into the smaller bowl and beat lightly with a fork.
Pour eggs into large bowl.
Pour in vegetable oil.
Stir gently until the dry ingredients are just moistened—don’t overmix.
Stir in chocolate chunks.
Put batter into the refrigerator and let it rest for 20 minutes.
Then use an ice cream scoop or large spoon to divide batter into cupcake liners.
Fill them close to the top.
Sprinkle with sparkling sugar, if desired.
Bake at 425 °F for 5 minutes, then reduce oven to 350 °F and bake another 10–12 minutes, or until muffins are golden brown and a toothpick comes out mostly clean (ignoring melted chocolate).
Let muffins cool for a few minutes in the pan, then transfer to a wire rack to cool fully (or enjoy warm).
Notes
Storage Tips: Store muffins in an airtight container at room temperature. They will stay fresh for three days, though if you use the sparkling sugar, the sugar will dissolve as time goes by. You can also freeze muffins in a freezer bag for up to 3 months, then thaw at room temperature.Expert Tips: As with all of my baking recipes, I strongly recommend weighing your ingredients using a kitchen scale. If you don’t have a scale, make sure to use the spoon and level technique when filling a measuring cup with flour or sugar.Don’t overmix the batter, as that leads to dense muffins. Leaving a few little streaks of flour in there is fine.If you like smaller muffins, fill the cupcake liners only ¾ of the way up. You’ll get 12 muffins out of this recipe, though they will not rise as high as muffin cups you have filled more.You can use frozen bananas in this recipe, but thaw them before using and pat dry with a paper towel to remove excess moisture before mashing.