Grease a nonstick muffin pan with nonstick spray or butter.
Whisk together the pumpkin, mashed banana, butter, and eggs in a large bowl.
Stir in the oat flour, sugar, baking soda, baking powder, cinnamon, ginger, nutmeg, and salt. Fold in the walnuts if using.
Divide the batter evenly between the muffin cups. Preheat the oven to 375℉ and rest the batter while it heats. Bake for about 20 minutes, or until a cake tester inserted into the center of a muffin comes out cleanly.
Cool the muffins in the pan for 5 minutes, then remove from the pan and cool on a wire rack completely before serving.
Notes
Make them mini. For perfectly handheld mini pumpkin banana muffins, well grease a mini muffin tin and portion out the batter. They will need less time to bake, about 15 minutes. If you add chocolate here, use mini chocolate chips, like in my
Swap all-purpose gluten-free flour - If you wish, you can use 2 ½ cups of your favorite 1:1 gluten-free flour blend or my homemade gluten free flour blend for the oat flour.
To make dairy-free - Use dairy-free butter or melted coconut oil for the unsalted butter.
To make refined sugar-free - Swap in ½ cup of pure maple syrup or ¾ cup coconut sugar for the granulated sugar.
Butternut squash or sweet potatoes - Try 1 cup of butternut squash puree (or make it yourself) in these muffins for a slightly different flavor! You can also make these into sweet potato muffins by using 1 cup of mashed sweet potatoes for the pumpkin puree.