Preheat oven to 350° F.
Melt ¼ c. butter in the baking pan
Mix in ½ cup brown sugar and 1 tsp vanilla with spatula and remove from heat. Spread mixture evenly in pan.
Align cut bananas around pan so they cover the bottom. Set aside.
Mix together flour, baking powder, and salt. Set aside.
Cream together butter, peanut butter, and sugar until fluffy. Scrape sides as needed.
Add mashed banana, egg, and vanilla. Slowly beat until well combined.
Slowly beat in flour mixture and milk alternating between the two. I did 3 additions of the flour mixture and 2 of the milk. Batter will be thick.
Mix chocolate chips with a bit of flour (1-2 tbsp). Toss to coat. This helps to keep the chocolate chips immersed in the batter while baking.
Add coated chocolate chips to batter and mix with a spatula until just combined.
Bake for 35-40 minutes or until a toothpick comes out clean.
Allow to cool for 5-10 minutes before flipping onto a serving plate.