Preheat the oven to 350°F. Lightly grease a mini muffin pan with cooking spray.

In a medium bowl, whisk together the flour, baking powder, salt, 1 teaspoon cinnamon, and 1 teaspoon pumpkin pie spice.

In a separate bowl, whisk the canola oil, brown sugar, egg, pumpkin puree, milk, and vanilla extract until smooth. Pour the wet ingredients into the dry ingredients and stir just until no streaks of flour remain.

Spoon the batter into the prepared mini muffin cups, filling each cup nearly to the top. Bake for 10 to 12 minutes, or until a toothpick inserted into the center of a donut comes out clean. Use the remaining batter to bake a second batch.

While the donuts bake, melt the butter in a microwave-safe bowl. In a separate shallow bowl, stir together the granulated sugar, 2 teaspoons cinnamon, and 1 teaspoon pumpkin pie spice.

Remove the baked donuts from the oven and turn them out onto a wire rack. Let them cool for a few minutes until they are warm but not too hot to handle. Roll each donut in the melted butter, then toss it in the cinnamon sugar mixture until evenly coated. Repeat with all the donuts.

If you are making these ahead of time, keep the donuts uncoated and store them separately. Coat them with butter and cinnamon sugar right before serving, because the sugar will melt into a glaze over time and the outside will lose its crisp texture.

Serve warm and enjoy every bite.