Begin by preheating the oven to 350 degrees F.
In a mixing bowl, combine the dry ingredients: flour, pumpkin pie spice, baking powder and salt. Mix thoroughly.
In a separate mixing bowl or stand mixer with paddle adjustment, combine the pumpkin puree, sugar, vegetable oil, melted butter, vanilla extract and eggs.
Slowly, add the dry ingredients to the wet ingredients. Mix until fully incorporated.
Using a spoon, fill three 6-cup nonstick donut pans with the batter until the mold is almost full. *You can also work in batches if you only have 1 or 2 donut pans.*
Use a mositened finger to evenly spread the batter onto the molds.
Bake the donuts for 15 minutes. Allow them to cool prior to transferring to a wire rack to finish cooling.
For the cinnamon sugar topping, stir the sugar and cinnamon together in a shallow bowl.
One at a time, dip one side of the donut into the melted butter and then into the cinnamon sugar mixture.
*Store the donuts tighly in plastic wrap or a ziplock bag. Donuts can last up to 5 days at room tempertuare or even longer in the fridge. Keep away from any source of heat.*