Preheat the oven to 350℉. Line muffin tins with 22 paper liners.
In a large bowl, cream together the butter and sugars until light and fluffy. Mix in the egg, sour cream, banana and vanilla until fully combined.
In a separate bowl, mix together the flour, cinnamon, salt, baking powder, baking soda and cocoa powder.
Slowly mix the dry ingredients into the wet ingredients until just combined.
Fold in around 1/2 cup of chocolate chips and 1/2 cup white chocolate chips.
Divide the batter evenly in the prepared muffin cups. Sprinkle the remaining chocolate chips and white chocolate chips on top.
Bake in the preheated oven for 20-22 minutes, or until a toothpick inserted into the center of a muffin comes out with a few crumbs on it.
Allow to cool in the pan for around 2 minutes before transferring to wire racks to cool completely.