Preheat oven to 425
Spray a muffin tin or use paper liners.
Combine the flour, baking powder, baking soda, salt, nutmeg and cardamom together in a bowl. Whisk well.
In a separate bowl or in the bowl of an electric mixer, add the bananas, butter, oil, sugar and brown sugar.
Mix well and add in the egg and the vanilla. Mix well.
Add in the dry ingredients and mix until just combined.
Fold in the chocolate chunks. Batter will be thick.
Divide the batter into the muffin tin cups.
Bake for 5 minutes then lower the temperature to 350 and continue baking for 15-18 minutes (until a toothpick in the centre comes out clean).
Allow the muffins to cool in the pan for 5 minutes, then transfer to a wire cooling rack to cool completely.