Ingredients 

1. 1 cup (170 g) dark chocolate chunks – I like to cut up a bar of 50% dark chocolate. Semi-sweet chocolate chips/drops will work too.
2. 1½ cups (339 g) very ripe bananas – mashed, about 3 large bananas
3. 1¼ cups (155 g) flour – plain, all purpose
4. 2 tbsp (16 g) cornstarch
5. 1 tsp baking powder
6. ¾ tsp baking soda
7. ½ tsp salt
8. ⅓ cup (35 g) cocoa powder – unsweetened, dutch process preferred
9. ¼ cup (56 g) unsalted butter – room temperature
10. ¾ cup (150 g) white granulated sugar
11. ¼ cup (52 g) unflavoured vegetable oil – I use canola oil
12. 1 large egg – room temperature
13. 1½ tsps vanilla extract/essence

Instructions

1. Preheat oven to 160 °C (320°F) with the fan on (see note 1 if you don’t have a fan function) and line an 8.5×4.5inch loaf tin (I like to lightly grease the tin before lining it so that the parchment paper sticks better).
2. If using a dark chocolate block, then cut it into small chunks and set aside for now.
3. Mash the bananas using a potato masher or fork and set aside for now.
4. Sift together flour, cornstarch, baking powder, baking soda, salt and cocoa powder. Using a whisk or fork, mix until well combined. Set aside for now.
5. In a large bowl combine butter, sugar and oil, and using a hand or stand mixer on a medium-high speed, cream together for 2 minutes until light and fluffy.
6. Next add in the room temperature egg and mix until well combined.
7. Next add in mashed bananas and vanilla, and mix until well combined. Once done, remove any remaining batter off of the attachment(s) and set your mixer aside as the rest of the mixing will be done by hand.
8. Add the pre-sifted dry ingredients from earlier into the wet mixture, along with 3/4s of the dark chocolate (around 130g). Using a spatula, gently fold until just combined. Do not overmix the batter.
9. Distribute the batter evenly into the prepared cake tin, and sprinkle the remaining 1/4 cup of dark chocolate on the top.
10. Drop the cake tin lightly on the counter to remove any large air bubbles, and bake for 65-75 minutes, or until a skewer or knife comes out mostly clean. There may be some melted chocolate on your cake tester, but as long as there isn’t any wet uncooked batter it’s done.
11. Allow to cool in the cake tin for about 20 minutes, before transferring to a wire rack or serving plate. Allow to cool for another 30 minutes before serving (I like mine slightly warm