Preheat your oven to 350°F (175°C) and grease a donut pan with cooking spray.

In a medium mixing bowl, blend together the pumpkin puree, brown sugar, vegetable oil, and milk until smooth.

In a separate bowl, sift together the all-purpose flour, baking powder, pumpkin pie spice, cinnamon, nutmeg, and salt.

Gradually fold the dry mixture into the wet ingredients, stirring gently until just combined.

Carefully transfer the donut batter into a piping bag and fill each cavity of the prepared donut pan.

Place the filled donut pan in your preheated oven and bake for 15-16 minutes.

Once baked, remove the pan from the oven and allow the donuts to cool for about 10 minutes.

Brush or dip each warm donut in melted butter, then roll it in a mixture of granulated sugar and cinnamon.