Preheat and prep: Set your oven to 350°F (175°C).
Line a 12-cup muffin tin with liners or lightly spray with nonstick spray.
Mix the wet ingredients: In a large bowl, whisk pumpkin puree, egg whites, applesauce, sweetener, vanilla, and almond milk until smooth.
Combine the dry ingredients: In a separate bowl, stir together white whole wheat flour, oat flour, baking powder, baking soda, salt, pumpkin pie spice, and cinnamon.
Bring it together: Add the dry ingredients to the wet ingredients. Stir gently until just combined. The batter will be thick—don’t overmix.
Portion the batter: Divide evenly among the muffin cups.
Fill each about 3/4 full. If using optional add-ins, sprinkle a few on top of each muffin.
Bake: Place on the middle rack and bake for 15–18 minutes, or until a toothpick comes out clean or with a few moist crumbs.
Cool: Let muffins sit in the pan for 5 minutes, then transfer to a wire rack to cool completely. This helps them set and stay tender.