01 - Preheat the oven to 350°F. Line a 12-cup muffin tin with paper liners or lightly grease all cups.
02 - In a large mixing bowl, whisk together the pumpkin puree, mashed banana, eggs, vegetable oil, milk, and vanilla extract until fully smooth.
03 - In a separate bowl, blend the all-purpose flour, granulated sugar, brown sugar, baking soda, baking powder, salt, cinnamon, nutmeg, and ginger until evenly combined.
04 - Add the dry mixture to the wet mixture and gently fold with a spatula until just combined, taking care not to overmix.
05 - Fold in the chopped nuts or chocolate chips, if using, distributing them evenly through the batter.
06 - Divide the batter evenly among the prepared muffin cups, filling each about three-quarters full.
07 - Bake for 20 to 22 minutes, or until a toothpick inserted in the center of a muffin comes out clean.
08 - Allow muffins to cool in the tin for 5 minutes, then transfer to a wire rack to cool completely before serving.