Grease a 9x5 inch loaf pan with cooking spray and set aside. Heat the oven to 350° F.

In a medium bowl, whisk together the flour, cocoa powder, baking soda and salt. Set the bowl aside.

In a large bowl with an electric beater, mash the bananas (you can also do this by hand). Add the melted butter and oil, and mix until combined. Mix in the brown sugar, egg and vanilla and stir until smooth.

Slowly add the dry ingredients to the wet ingredients. Fold in the chocolate chips and peanut butter chips, saving a bit of each to sprinkle on the top of the loaf. Pour about half of the batter into the loaf pan and smooth out. Drizzle the melted peanut butter on top of the batter and swirl with a knife. Then pour the other half of the batter on top. Sprinkle the remaining chocolate and peanut butter chips on the top of the batter.

Bake for 60-65 minutes, or until a toothpick inserted into the middle of the loaf comes out clean. Let the loaf cool for 15-30 minutes before serving.