Preheat an oven to 180°C or 350°F. Grease a muffin tray or line it with paper cupcake cases.
In a medium mixing bowl, mash your banana well with a fork.
Mix in the maple syrup and melted butter. Then beat in the egg and vegetable oil.
Finally add the vanilla extract and natural yogurt.
Pour in your dry ingredients to the bowl starting with the self-raising flour. Then add the cocoa powder, baking powder and baking soda.
Mix until just combined. You should have a thick chocolatey batter.
Spoon the mixture into each of your cupcake cases until about ⅔ full.
Bake on the middle shelf of the oven for 20 minutes or until a toothpick comes out clean.
Let the cupcakes cool to room temperature while you make the icing.