Preheat the oven to 350°F. Line a loaf pan with parchment paper and keep it aside.
In a mixing bowl, combine the butter, eggs, banana, vanilla extract, and sugar, and whisk until well incorporated.
½ cup Butter, 2 Eggs, 1 ½ cups Bananas, 1 teaspoon Vanilla extract, ¾ cup Sugar
To this, add flour, cocoa powder, salt, and baking soda, and mix. Do not overmix.
1 ½ cups Flour, ½ cup Cocoa powder, ¾ teaspoon Salt, 1 teaspoon Baking soda
Fold in the chocolate chunks.
½ cup Milk chocolate, ½ cup Dark chocolate
Pour the batter into the prepared loaf pan and sprinkle some more chunks on top.
Bake for 50 to 55 minutes or until a toothpick inserted comes out clean.
Cool completely before slicing.