Preheat the oven to 350F (175C) and spray a 9x5 loaf pan with nonstick cooking spray.
In a large bowl, mash together the banana, avocado, egg, and vanilla. Do not overmix, it’s OK if it has a chunky texture.
3 ripe bananas, ½ ripe avocado, 1 large egg, 1 teaspoon vanilla extract
In another bowl, whisk together the all-purpose flour, granulated sugar, unsweetened cocoa powder, baking soda, cinnamon, and salt.
1 ¼ cups all-purpose (plain) flour, ¾ cup granulated sugar, ¼ cup unsweetened cocoa powder, 1 teaspoon baking soda, 1 teaspoon ground cinnamon, ½ teaspoon fine sea salt
Add the dry flour mixture to the banana mixture and stir to combine. Again, do not overmix.
Gently fold in the semisweet chocolate chips.
Pour the banana bread batter into the prepared loaf pan. Sprinkle the top of the batter with more semisweet chocolate chips and pop into the preheated oven.
Bake for about 1 hour, or until a toothpick or skewer inserted into the centre of the loaf comes out clean.
Remove from the oven and allow to cool in the load pan for about 5 minutes before transferring to a wire cooling rack and allowing to cool completely.