Preheat oven to 350 degrees and spray a donut baking pan with non-stick spray.
In a large bowl, sift together the AP flour, cake flour, baking powder, baking soda, salt, and pumpkin spice. Add the granulated sugar and brown sugar to the bowl and whisk everything together until well combined.
In a medium-sized bowl, combine the canned pumpkin, eggs, vanilla, melted butter, vegetable oil, and vanilla creamer (or half and half, if substituting). Mix until well combined.
Add the wet ingredients to the dry ingredients and stir until just combined.
Pour the pumpkin batter into a piping bag (or gallon-sized plastic bag with the corner cut) and fill the donut pan with the batter. Make sure to not overfill the donut molds.
Bake for 12-15 minutes until the donuts are cooked through and pass a toothpick test (Insert a toothpick, if it comes out clean, they’re done). Let the donuts sit in the warm donut pan for about 5 minutes until they are still warm, but cool enough to handle.
In the meantime, melt 3 tbsp of unsalted butter in a bowl. Place the granulated sugar and cinnamon into a second bowl and stir until combined.
Lightly dip the tops of the donuts into the melted butter and then into the cinnamon-sugar. Best eaten fresh. Store leftovers in an air-tight container.