Preheat the Oven
Preheat oven to 350°F (175°C).
Grease or line a 9×5-inch loaf pan with parchment paper.
Mash the Bananas
In a large bowl mash the ripe bananas with a fork until mostly smooth.
Mix the Wet Ingredients
Add peanut butter, melted butter (or oil), brown sugar, granulated sugar, eggs, and vanilla extract.
Whisk until smooth and fully combined.
Combine the Dry Ingredients
In a separate bowl whisk together flour, baking soda, salt, and cinnamon.
Make the Batter
Add the dry ingredients to the banana mixture and stir gently until just combined.
Avoid overmixing.
Create the PB&J Swirl
Pour half of the batter into the loaf pan.
Add half of the jam and peanut butter on top and gently swirl with a knife.
Add the remaining batter and repeat the swirl.
Bake
Bake for 50–60 minutes, or until a toothpick inserted into the center comes out clean.
If the top browns too quickly, loosely cover with foil.
Cool and Slice
Allow the bread to cool for 10–15 minutes in the pan.
Transfer to a rack and cool completely before slicing.