Preheat oven to 350 degrees F. Spray a donut pan with cooking spray.

In a large bowl, whisk together the flour, baking powder, cinnamon, ginger, nutmeg, allspice, cloves, and salt.

In a separate large bowl, whisk together the pumpkin, brown sugar, oil, melted butter, eggs, milk, and vanilla until completely combined.

Stir the flour mixture into the pumpkin mixture, stirring until just combined.

Carefully spoon the batter evenly around the circles of the donut rings, filling each nearly to the top.

Bake for about 12 minutes, until donuts spring back when gently pressed and a toothpick inserted into one comes out clean.

Turn the donuts out onto a wire rack and allow to cool.

While the donuts are cooling, prepare the cinnamon sugar coating: melt the butter in one bowl and whisk the granulated sugar and cinnamon in another.

Working with one donut at a time, use a pastry brush to spread a thin layer of butter onto the donut before dipping it into the cinnamon sugar to coat all sides. Repeat with the remaining donuts.