Preheat oven to 350°F and line a muffin tin with paper liners (or spray lightly with nonstick spray).
In a large bowl, whisk together pumpkin, eggs, maple syrup, almond butter, Greek yogurt, and vanilla until smooth.
Add oat flour, protein powder, baking powder, baking soda, pumpkin pie spice, and salt. Stir until just combined—don’t overmix.
Fold in chocolate chips if you’re adding them.
Divide batter evenly among 12 muffin cups (about 3/4 full).
Bake 18–20 minutes, or until a toothpick comes out clean.
Let cool for at least 10 minutes before removing from the pan (if you can wait that long).