01 - Preheat oven to 350°F. Line a standard 12-cup muffin tin with paper liners or grease each cup lightly.
02 - In a large mixing bowl, whisk together pumpkin puree, mashed banana, eggs, vegetable oil, milk, and vanilla extract until smooth and homogenous.
03 - In a separate bowl, combine all-purpose flour, granulated sugar, brown sugar, baking soda, baking powder, salt, ground cinnamon, nutmeg, and ground ginger.
04 - Add dry ingredients to the wet mixture and gently stir until just combined. Avoid overmixing to ensure tender muffins.
05 - Fold in chopped walnuts, pecans, or chocolate chips if desired, distributing them evenly throughout the batter.
06 - Divide batter evenly among the 12 prepared muffin cups, filling each approximately three-quarters full.
07 - Place the tin on the center oven rack and bake for 20 to 22 minutes, or until a toothpick inserted into the center of a muffin emerges clean.
08 - Allow muffins to cool in the tin for 5 minutes, then remove and transfer to a wire rack. Let cool completely before serving.