- With the rack in the middle position, preheat the oven to 180 °C (350 °F). Line a 23 x 13-cm (9 x 5-inch) loaf pan with a strip of parchment paper, letting it hang over both sides. Butter the other two sides.
- In a bowl, combine the flour, baking powder, and baking soda. Set aside.
- In another bowl, cream the butter with the brown sugar, cocoa powder, and vanilla with an electric mixer. Add the eggs, one at a time, and beat until smooth.
- On low speed, add the bananas and dry ingredients alternately with the milk. Add the chocolate and combine. Pour into the prepared pan and sprinkle with the peanuts.
- Bake for about 1 hour or until a toothpick inserted in the centre comes out clean but slightly topped with melted chocolate. Let cool for at least 1 hour and unmould. Serve warm or cold.