In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and cinnamon until evenly combined. Set the dry ingredients aside.
1⅓ cups all-purpose flour, 1½ teaspoons baking powder, ½ teaspoon baking soda, ½ teaspoon sea salt, ½ teaspoon ground cinnamon
In a separate large bowl, whisk together the large eggs, mashed bananas, light brown sugar, and granulated sugar until well blended.
1 cup mashed overripe bananas, 1/2 cup packed light brown sugar, 1/3 cup granulated sugar, 2 large eggs
Add in the creamy peanut butter, vegetable oil, melted butter, and vanilla extract and whisk until the mixture is smooth and evenly combined.
1/3 cup creamy peanut butter, 2 tablespoons vegetable oil, 1 tablespoon butter, 2 teaspoons vanilla extract
Dump the bowl of dry ingredients into the larger bowl of wet ingredients, and gently fold with a wooden spoon or rubber spatula until no flour streaks remain in the batter. The batter will be thick.
Stir in the chocolate chips just until combined.
2/3 cup semi-sweet chocolate chips
Divide the muffin batter evenly among the 12 muffin cups, filling them about 90% full, leaving just a small space below the rim of the muffin cup for domed tops.
Bake at 400℉ for 7 minutes, then reduce the temperature to 350℉ without opening the oven door. Bake for an additional 10-12 minutes, until the tops are domed and a toothpick inserted into the center comes out with just a few moist crumbs.
Remove the muffin pan from the oven and place it on a wire cooling rack for 10 minutes. Lift the muffins out of the muffin pan to cool completely on the wire rack.