1. Preheat the oven to 375℉ and line a standard muffin tin with paper liners.
2. In a large bowl, whisk together the pumpkin puree, applesauce, eggs, olive oil, vanilla extract, and brown sugar.
3. Once those ingredients are well combined, whisk in the baking powder, baking soda, salt, and pumpkin pie spice.
4. Then, stir in the flour, rolled oats, and walnuts a little, don't over-mix.
5. Once the muffin mixture is ready, spoon the batter into the muffin liners, place the muffin tin in the hot oven, and let the muffins bake for 20 to 23 minutes.
6. After that time, remove the muffins from the oven, let them cool for 10 to 12 minutes.
7. Once the muffins are cooled, dig into a serving or store them in an air-tight container in the fridge until ready to enjoy!