Heat your oven to 350°F. Grease a 9-by-5-inch loaf pan with nonstick cooking spray and set aside.
In a medium bowl, whisk together the flour, cocoa powder, baking soda, and salt. Set aside.
In a large bowl, mash the ripe bananas with a fork. Add the melted butter and oil and stir until combined. Stir in the brown sugar, egg, and vanilla extract. Stir until smooth.
Stir the dry ingredients into the wet ingredients, don’t overmix. Gently fold in the chocolate chips.
Pour half of the batter into the prepared loaf pan. Drop spoonfuls of the peanut butter on top of the batter. Swirl the peanut butter into the chocolate batter with a butter knife. Top with remaining chocolate batter. Sprinkle the peanut butter chips over the top of the bread. Bake for 60-65 minutes, or until a toothpick inserted into the center of the bread comes out mostly clean, you might have some melted chocolate chips or peanut butter on the toothpick and that is fine. You just don’t want a lot of gooey batter.
Remove the pan from the oven and set on a wire cooling rack. Let the bread cool in the pan for 15 minutes. Run a knife around the edges of the bread and carefully remove from the pan. Let the bread cool on the wire cooling rack until slightly warm. Cut into slices and serve.
Note-the bread will keep on the counter, wrapped in plastic wrap, for up to 4 days. This bread also freezes well. To freeze, cool the bread completely and wrap in plastic wrap and aluminum foil. Freeze for up to 1 month. Defrost before slicing.