Preheat the oven to 350°F. Spray the bottom and sides of two non-stick metal 9x5 -inch loaf pan OR two 8x4-inch loaf pans with baking spray or butter and flour.
Using an electric mixer cream together the peanut butter, softened butter and vanilla for 2 minutes until fluffy.
Add the granulated sugar and brown sugar. Beat on medium-high for 2 minutes or until fully combined.
Add the eggs one at a time mixing well after each addition. Increase the speed of the mixer and beat for 30 seconds until the wet ingredients are light beige in color. Stop and scrape the sides of the bowl periodically.
Lower the speed of the mixer and gradually add the flour alternately with the yogurt beginning and ending with flour. After all has been added, beat just until fully combined scraping the bottom and sides of the bowl.
Fold in the mashed banana and Reese's by hand until fully incorporated.
Use a measuring cup to divide the batter between the two pans.
Bake for 35 minutes then check for browning. Lay foil on top, if needed.
Continue to bake another 15-20 minutes or until a toothpick inserted into the center comes back clean.
Cool in the pan for 15 minutes them remove from pans and place on a cooling rack to cool completely.
Notes
Use Overripe Bananas - The more ripe the bananas the sweeter they become. They may look ruined but they make the best banana bread.
Peanut Butter - You could use crunch peanut butter in place of creamy peanut butter. I don't recommend using natural peanut butters as they can separate and effect the texture of the batter.
Self Rising Flour - You can add 1 teaspoon baking powder, 1 teaspoon baking soda and 1/2 teaspoon salt to 3 cups of all purpose flour to make this bread. Use a whisk to sift the dry ingredients together then proceed with the recipe as written.
Nuts - You could add 1/2 cup chopped peanuts to the banana bread.
Greek Yogurt - You can replace the Greek yogurt by using the same amount of full fat sour cream.
Reese's Cups - You can use semisweet chocolate chips, milk chocolate chips or dark chocolate chips.