Preheat the oven to 350°F. Line a muffin pan with 10 paper liners.
In a mixing bowl, mix together pumpkin puree, vegetable oil, eggs, pumpkin pie spice, granulated sugar, baking soda, and salt. Mix until combined.
In another bowl, sift together all-purpose flour and baking powder. Then, add to the wet ingredients. Mix until combined and flour just disappears. Don't over mix the batter.
Spoon the pumpkin batter evenly into the prepared muffin cups. The muffin cups should be nearly full.
In a small bowl, mix together ground cinnamon and granulated sugar. Sprinkle this mixture over the pumpkin muffins.
Bake these easy pumpkin muffins in the preheated oven for 20-25 minutes or until ready. Check the readiness of the pumpkin muffins using a toothpick inserted in the center, if it comes out clean - easy pumpkin muffins are ready. Then, remove the muffin tin from the oven and let the pumpkin muffins cool to room temperature. Enjoy!