Preheat oven to 350 degrees F. Coat a 9×5 loaf pan with cooking spray and set aside. Using a stand mixer fitted with the paddle attachment (or a large mixing bowl with a hand mixer), combine the butter, brown sugar, eggs and vanilla and beat until combined.
In a separate bowl, combine the flour, baking powder, baking soda, salt and pumpkin pie spice. Mix well. Gradually add to the butter mixture and beat on medium-low speed until just combined. Stir in the pumpkin and bananas.
Pour the batter into the prepared pan, spreading in an even layer. Sprinkle chocolate chips over the top, if desired. Bake in the preheated oven for 60-70 minutes, or until a toothpick inserted into the center comes out clean. Let sit in the pan for 10 minutes before removing and serving.