Step 1

Preheat oven to 325°F / 163°C.

Step 2

Spray a loaf pan with nonstick cooking spray.

Step 3

In a large mixing bowl, whisk together melted butter, mashed banana, and brown sugar until evenly combined (it will be slightly lumpy). Whisk in eggs and vanilla.

Step 4

In a second bowl, whisk together flour, peanut butter powder, baking soda, and salt.

Step 5

Pour dry ingredients over wet and stir just until no dry spots remain.

Step 6

Stir chocolate chips into batter.

Step 7

Pour batter into prepared loaf pan. Spoon peanut butter over the top of the batter. Using a knife, draw swirls through the peanut butter so that it blends into the batter. Scatter a few chocolate chips on top.

Step 8

Bake bread until the center is set, 60 to 70 minutes.

Step 9

Allow to cool before slicing and serving.