Preheat oven to 350F. Spray a donut pan with non stick spray and set aside.
In a medium-sized bowl, combine ¾ cup brown sugar, ¼ cup of white sugar, the oil and an egg. Whisk thoroughly to combine.
Add the pumpkin puree, 2 tablespoon melted butter, and vanilla extract when combined.
Combine all-purpose flour, 2 teaspoons of cinnamon, salt and baking soda in a large bowl. Whisk to combine.
Pour the wet ingredients into the dry, and mix with a rubber spatula until combined.
Fill donut pans with about ¼ cup of batter. I usually put my batter into a Ziploc bag, cut the corner and pipe it into the pan.
Bake at 350F for 10-14 minutes. Cool for 5 minutes, then transfer to a wire cooling rack.
In a medium bowl, combine the remaining ¼ cup of white sugar and 3 tablespoons of ground cinnamon. Whisk to combine.
Once cooled, dip the donuts in melted butter or use a pastry brush to brush them in butter. Dip them in the cinnamon-sugar mixture until coated well. Serve and enjoy!
Notes
When combining the wet and dry ingredients, avoid overmixing the batter. Doing this will cause the donuts to become dense when they're baked.
Remember to preheat the oven before you add in the donut tin. This is important, as the hot oven helps the donuts fluff up nicely and get that crispy texture on the outside.
Don't want to top the donuts with the cinnamon sugar mixture? Drizzle a bit of maple syrup over them and finish up with a sprinkle of your favorite chopped roasted nuts like pecans and walnuts, or just keep it simple and drizzle some chocolate sauce over them.
If you don't have a donut tin, you can also make donut holes by adding the batter in mini muffin tins. Just remember that the cooking time will reduce if you're doing this.