Preheat the oven to 350 degrees. Heavily grease a 12-cup muffin pan with vegetable spray. Combine the cake mix with the can of pumpkin puree. I used a hand mixer, scraping the sides often. Scoop the mixture evenly into the 12 muffin cups. Bake for 35-45 minutes depending on how thick your muffin tin pan is. To test for doneness use a toothpick to see if the muffins are done by coming out clean. These are so moist!