Begin by preheating your oven to 350 degrees F. Spray your baking pan(s) with a nonstick cooking spray and set aside.
In a large bowl, whisk together the flour, cinnamon, nutmeg, allspice, cloves, baking powder and salt.
In a medium bowl, whisk together the pumpkin puree, milk, brown sugar, vegetable oil, egg, and vanilla.
Add the wet mixture to the dry. Stir with a spatula until just combined.
Scoop the batter into the muffin tray. The cavity should be almost completely filled. If you're using a mini muffin pan to create donut holes, the dough should be rounded on the top.
Bake for 10-12 minutes or until a toothpick inserted near the center comes out clean.
In a small bowl, prepare the cinnamon-sugar topping by mixing together the cinnamon and sugar.
When the donuts are baked, cool them for about 5 minutes. Then rub or brush the melted butter on each donut and coat it in the cinnamon-sugar mixture.
Allow to cool or enjoy warm.