Preheat your oven to 350°F (175°C). Grease the loaf pan or line it with parchment paper for easy removal.
In a large mixing bowl, combine the mashed bananas, pumpkin puree, vegetable oil, eggs, granulated sugar, brown sugar, and vanilla extract. Whisk until smooth and well mixed.
In a separate bowl, whisk together the flour, baking soda, baking powder, salt, cinnamon, nutmeg, and ginger.
Gradually add the dry ingredients to the wet ingredients, stirring with a rubber spatula until just combined. Be careful not to overmix; a few lumps are okay.
If using, fold in the chopped walnuts or pecans.
Pour the batter into the prepared loaf pan, smoothing the top with the spatula.
Bake in the preheated oven for 55-60 minutes or until a toothpick inserted into the center comes out clean.
Once baked, remove from the oven and allow the bread to cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.
Store any leftover pumpkin banana bread in an airtight container at room temperature for up to 3 days or refrigerate for up to a week.
This recipe can also be frozen for up to 3 months; just ensure it is well-wrapped.
For added flavor, consider adding chocolate chips or dried cranberries to the batter.