Pre heat oven to 350°F and place the rack the center of the oven.
Fill a 12-count muffin tin with cupcake liners.
In a large mixing bowl, thoroughly whisk together dry ingredients, breaking up most of the cocoa clumps.
In a second mixing bowl, whisk together wet ingredients and the mashed bananas.
Pour wet ingredients over dry ingredients and whisk just until the ingredients come together and no dry streaks remain. Batter will be a little loose and lumpy.
Use a Ice-cream scoop or a spoon to portion batter, filling each cup 2/3 full (do not over-fill). Bake 20 minutes - that was the perfect time for me or up to 22 minutes until a toothpick inserted in the center, comes out clean. Cool 5 minutes in the pan then transfer to a rack to cool completely to room temperature before frosting.
Notes
do not over-fill the cup cake liners
Bake 20-22 minutes depends on the oven you have
you can freeze them if you like without frosting. To defrost leave in the fridge overnight