Preheat the oven to 350ºF. Butter a 9 x 5 x 3-inch loaf pan. Set aside.
With an electric mixer, or stand mixer, cream the butter and sugar until light and fluffy. Add the eggs, beating well.
Sift the dry ingredients together and combine with the butter mixture. Blend well. Add the bananas, pumpkin puree, and vanilla. Stir well. Stir in the chocolate chips and nuts, if using, and pour into the prepared pan.
Bake 1 hour & 10 minutes, until a cake tester comes out clean. Turn out onto a cooling rack and allow to rest until cooled.