Prep the pan. Heat the oven to 350°F (175°C).
Line a 12-cup muffin tin with liners or lightly grease.
Whisk the wet ingredients. In a large bowl, whisk pumpkin, eggs, Greek yogurt, milk, oil, maple syrup, and vanilla until smooth and glossy.
Combine the dry ingredients. In a separate bowl, stir together oat flour, whole wheat flour, protein powder, baking powder, baking soda, cinnamon, pumpkin pie spice, and salt. Break up any lumps, especially in the protein powder.
Bring it together gently. Add the dry mix to the wet mix. Stir with a spatula until just combined.
The batter should be thick but scoopable. If it’s too dry, add 1–2 tablespoons of milk.
Fold in extras. If using chocolate chips, nuts, or seeds, fold them in now. Don’t overmix.
Portion and bake. Divide batter evenly among the 12 cups.
For bakery-style tops, fill almost to the rim. Bake 17–20 minutes, or until a toothpick comes out with a few moist crumbs.
Cool smartly. Let muffins rest in the pan for 5 minutes, then transfer to a wire rack. Allow to cool completely for the best texture.
Enjoy. Eat warm or at room temp.
They’re great with a smear of almond butter.