Lightly grease 12 muffin cups, or line with muffin papers.
In a bowl, mix together flour, baking powder and baking soda
In a large bowl, mix together bananas, sugars, egg and oil, and vanilla. Gradually add the flour mixture into the banana mixture just until moistened.
Spoon ⅓ of the muffin batter into another bowl. Stir the cocoa powder and boiling water together until smooth, and then stir the cocoa mixture into the batter that you set aside.
Spoon a dollop of regular into each muffin well- just enough to cover the bottom. Follow with a dollop of chocolate batter, another small spoon of regular and then a small little spoon of chocolate, filling to a maximum of ¾ of the way.
Use a toothpick or skewer to swirl all the batter together, and sprinkle a few chocolate chips on top.
Bake for 20-25 minutes or until muffins are golden and a toothpick inserted into the center comes out clean.
Recipe by The Baker Chick at https://www.thebakerchick.com/dark-chocolate-banana-swirl-muffins/