Preheat your oven to 350°F (175°C). Line a 12-cup muffin pan with paper liners or lightly grease each cup. Preparing the pan first helps the muffins bake evenly and release easily after baking.

In a large mixing bowl, whisk together the flour, baking powder, baking soda, cinnamon, pumpkin pie spice, and salt. Mixing the dry ingredients separately ensures the spices and leavening agents are evenly distributed.

In a medium bowl, add the pumpkin puree, cottage cheese, eggs, brown sugar, maple syrup, vegetable oil, and vanilla extract. Whisk until smooth and fully blended. The mixture should look creamy and well combined.

Pour the wet mixture into the bowl of dry ingredients. Stir gently with a spatula until no dry flour remains. Avoid overmixing because that can make the muffins dense instead of soft and tender.

Divide the batter evenly among the prepared muffin cups. Fill each cup about three-quarters full. If using the topping, combine the oats, brown sugar, and cinnamon, then sprinkle over each muffin.

Place the muffin pan in the preheated oven. Bake for 18 to 20 minutes until the tops are lightly golden. A toothpick inserted into the center should come out clean when done.

Remove the muffins from the oven and let them cool in the pan for five minutes. Transfer them to a cooling rack and allow them to cool slightly before serving and enjoying.