Preheat the oven to 425F and line a cupcake tin with 12 parchment paper liners. This recipe makes 14 muffins so if you have another pan, fill with 2 liners.
In a large mixing bowl, whisk together the flour, brown sugar, sugar, baking powder, baking soda, salt, and chocolate chips.
Mash and measure the banana to exactly 1 ½ cups. If you’re short, supplement with unsweetened applesauce.
In a separate bowl, mix together the banana, olive oil, eggs, vanilla, and sour cream.
Pour the wet ingredients into the dry ingredients and mix to combine.
Scoop the batter into the liners, filling all the way to the top. Sprinkle with extra chocolate chips if desired.
Bake at 425F for 10 minutes, then turn the oven to 350F and bake for another 5-7 minutes.
Allow the muffins to rest in the pan for 5 minutes, then carefully transfer to a cooling rack.
Enjoy while they’re still warm! But they’re just as delicious the next day.