Preheat the oven to 400 degrees
Measure the coconut oil while solid, then transfer to a bowl and microwave until melted. Allow it to cool slightly
In a large bowl, whisk together the greek yogurt, mashed banana, eggs, sugar, vanilla extract, and melted coconut oil until well combined
In a separate bowl, whisk together the flour, cocoa powder, salt, baking soda, and baking powder
Add the dry ingredients to the wet, and use a rubber spatula to mix until JUST combined (do not over mix as it will cause denser muffins)
Fold the chocolate chips into the batter
Line a muffin tin with parchment paper muffin liners (these will not stick at all)
Distribute the healthy chocolate muffin batter evenly into 12 muffin cups, about ¾ of the way full. Sprinkle additional chocolate chips on top of the muffin batter
Bake the chocolate muffins at 400 degrees for 14 - 17 minutes, or until a toothpick inserted comes out clean