Set oven to 350°F (175°C). Line a muffin tin with paper liners or lightly grease with cooking spray.
Add cottage cheese, eggs, pumpkin puree, sweetener, and vanilla extract to a blender. Blend until smooth, about 1–2 minutes.
In a bowl, whisk oat flour, protein powder, baking powder, pumpkin pie spice, and salt until well combined.
Pour wet ingredients into the dry mixture. Stir gently with a spatula until just combined. Do not overmix.
Spoon batter evenly into muffin cups, filling each about ¾ full.
Bake for 18–20 minutes, or until a toothpick inserted in the center comes out clean.
Let muffins rest in the tin for 5 minutes, then transfer to a wire rack to cool before serving.
