Preheat oven to 375F and grease muffine tin
In a large mixing bowl, mash the bananas until only small lumps remain
Add yogurt and egg, and whisk until combined
Add oil, milk, and vanilla and stir to combine
Add the granulated and light brown sugar ands stir until combined
If using cocoa powder, stir in with a spatula scraping down the sides of the bowl as needed. Mix until the cocoa is completely combined
Stir in salt and baking soda
Gently fold in flour until just combined
If using chocolate chips, add and mix until evenly mixed throughout
Fill 12 muffins cups about 3/4 full with batter
Bake 16-19 minutes, rotating once halfway through