Preheat oven to 350 degrees. Grease the mini-donut pan.
Whisk together flour, baking powder, salt, cinnamon, nutmeg, allspice and cloves in a small bowl.
Combine oil, brown sugar, egg, vanilla extract, pumpkin and milk in a large bowl. Slowly add the flour mixture to the wet ingredients and stir until just combined. (Don't overwork the batter. No one likes tough donuts.)
Pour batter into a large ziploc bag and snip a small corner off one end. (You're essentially making a pastry bag.) Squeeze batter into mini-donut pan forms, working in stages if necessary. Bake for 7-9 minutes. If the donuts gently spring back when you touch them, they are ready. Pop them out onto a wire rack to cool.
Coating
Combine the cinnamon and sugar in a bowl.
Working with a few donuts at a time, brush both sides of donuts with butter using a pastry brush (or dip them right into the butter.)
Put donuts into bowl and coat with cinnamon-sugar.
Notes
If you don't plan to eat all the donuts right away, place the uncoated donuts in an airtight container until ready to use. Then proceed with the butter/sugar coating when you are ready to serve them.