Preheat the oven to 375℉/190℃ and line a muffin tin with liners and set aside.
In a bowl, add the flour, sifted cocoa, baking soda, baking powder, cornstarch, and salt. Stir to combine and set aside.
1 3/4 cups all-purpose flour, 1/3 cup unsweetened cocoa powder, 1 tsp baking soda, 2 tsp baking powder, 2 tsp cornstarch, 1/4 tsp salt
In a large bowl, add the ripe bananas, brown sugar, eggs, oil, and vanilla. Whisk to combine.
1 1/2 cups ripe bananas, 2/3 cups oil, 3/4 cups dark brown sugar, 2 large eggs, 1 tbsp vanilla
Add the dry ingredients and with a spatula, fold gently just until a muffin batter forms.
Mix in the chocolate chips gently a few times - do not over-mix!
3/4 cups semi-sweet chocolate chips
Scoop and divide the batter evenly between the liners. Sprinkle extra chocolate chips on top if desired.
Bake for 22-28 minutes or until a toothpick inserted comes out clean. Allow to cool, and enjoy!