Preheat the oven to 350°F and move the rack to the bottom third position. Grease a 9x5-inch loaf pan or line with parchment paper and set aside.
In a large bowl, whisk together the flour, baking soda, salt, and cinnamon. Set aside.
2 cups all-purpose flour, 1 teaspoon baking soda, ¼ teaspoon salt, ½ teaspoon cinnamon
Using a standing mixer fitted with the paddle attachment or a handheld mixer and large bowl, beat the butter until pale and fluffy. Add the brown sugar and mix on medium high speed for 1 minute until smooth. Add the bananas, mixing until mashed. Scrape down the sides and bottom of the bowl. Add the peanut butter and mix until combined, scraping down the bowl halfway.
½ cup unsalted butter, ¾ cup packed light brown sugar, 3 large bananas, ⅓ cup creamy peanut butter
Lower the speed to medium and add the eggs one at a time, beat well after each addition. Add the sour cream and vanilla extract and mix for about 30 seconds on medium speed. Reduce the speed to low, add the dry ingredients and mix until just combined. Finish mixing with a spatula if needed.
2 large eggs, ⅓ cup full fat sour cream, 1 teaspoon pure vanilla extract
Transfer the batter into the prepared pan and sprinkle with chocolate chips (optional). Tent the pan with aluminum foil and bake covered for 30 minutes. Remove the foil and bake for another 30 minutes. To check the doneness, insert a toothpick into the center of the loaf. If it comes out clean or just a little crumbly, the bread is done.
½ cup semi sweet chocolate chips