Preheat oven to 350 degrees F. Combine butter and sugar in the bowl of an electric mixer with paddle attachment. Cream together until combined. Add in eggs, one at a time. Add in canned pumpkin and mix until combined. Add in flour, baking soda, and pumpkin pie spice. Stir until combined. Stir in ripe bananas (mashed) and vanilla extract until mixed.
Pour into two regular-sized bread loaf pans. Bake for 1 hour and 20 minutes. Oven times will vary, so insert a knife (or long skewer stick) into center to test for doneness.
Don't have pumpkin pie spice? Don't worry! Combine 3 tablespoons ground cinnamon, 2 teaspoons ground ginger, 2 teaspoons ground nutmeg, 1 ½ teaspoons ground allspice and 1 ½ teaspoons ground cloves. This recipe makes two loaves! I cut approximately 12 slices per loaf.