Preheat your oven to 350°F.

In a large mixing bowl, whisk together your melted butter, brown sugar, and ½ cup of granulated sugar until just combined.

Add the eggs and whisk again. Once the eggs have been thoroughly beaten and the mixture is homogeneous, whisk in the pumpkin puree.

Gently whisk in the flour, baking powder, baking soda, and ½ tablespoon of ground cinnamon. Once the dry ingredients and wet ingredients are combined, spoon the donut batter into a donut tin, filling each mold up most of the way.

Bake your donuts for 15 minutes and then let them cool in the pan for 5 minutes. While they cool, whisk together the remaining cinnamon and granulated sugar in a small bowl.

Transfer your donuts to a wire cooling rack and brush them with melted butter. Dip each donut in the cinnamon sugar mixture.