Preheat your oven to 350° and lightly grease two 6-well donut pans with nonstick baking spray. 

In a large bowl, whisk together the milk, pumpkin puree, melted butter, egg, and vanilla. 

Next, add the flour, brown sugar, baking powder, and pumpkin pie spice. Mix just until no large lumps of flour remain—you don't want to overmix! 

Transfer the batter to a piping bag (or a ziploc bag with the end cut off) and pipe the batter into the prepared pans. Fill each section about ½ full– these donuts will rise quite a bit! 

Bake for 16-18 minutes, or until a toothpick inserted into the donuts comes out clean. 

Transfer the donuts to a wire rack and cool completely before frosting. 

For the frosting, whisk together the powdered sugar, vanilla, and 2 tablespoons of milk. If you would like a thinner frosting, add another tablespoon of milk. This frosting can be thick and spreadable or thin like a glaze—it’s completely up to you! To make it thicker, add more powdered sugar. To make it thinner, add more milk. 

Frost the donuts as desired and sprinkle with a pinch of pumpkin pie spice. Allow the frosting to set (about 10 minutes) and enjoy. 

Store any leftover donuts in an airtight container in the fridge for up to three days.