Preheat oven to 350 degrees F. Spray a regular loaf pan or 3 mini loaf pans with nonstick cooking spray. Set aside.
Cream butter in a stand mixer until light and fluffy, about 3 minutes. Add sugar and beat another 2 minutes. Add eggs, one at a time, mixing well between each addition.
Add flour, baking powder, baking soda and salt in a medium sized bowl. In another bowl, mix together the vanilla, bananas and peanut butter.
Alternate adding dry ingredients and banana mixture, starting and ending with dry ingredients. Mix until just incorporated. Stir in chocolate chips.
Pour into one large loaf pan or evenly among 3 mini pans. Bake the large loaf for 50 to 60 minutes, until a toothpick comes out clean. If you're baking minis, 30 to 40 minutes.