Preheat oven to 350ºF. Grease a standard 4.5” x 8.5” bread loaf pan.
In a bowl whisk together flour, cocoa and baking soda.
In another bowl, cream margarine and sugar. Add mashed banana and egg.
Add dry ingredients to banana mixture. Add chocolate chips and stir to combine. Pour into prepared pan. Bake for 55-60 minutes.
Remove from oven allow to cool for 10 minutes. Turn out onto a baking rack and allow to cool completely.
Make Simple Chocolate Icing and frost top of loaf.