Preheat oven to 350°F. Spray a 6-count donut pan with non-stick spray.
In a medium bowl, mix together the flour, baking powder, pumpkin pie spice and salt. In a separate large bowl, mix together the pumpkin puree, brown sugar, milk, butter, egg and vanilla extract. Add the dry ingredients to the wet ingredients and mix together until just combined.
Spoon the batter into the donut molds, filling to just below the top of each mold. (about ⅛" from the top) Bake for 15-18 minutes or until a toothpick inserted in the middle of a donut comes out completely clean. Remove from the oven and let cool for 5 minutes. Slide a thin spatula around edges of the donuts to loosen the them. Place on cooling rack and let completely cool.
Once donuts are cool, dip in to the chocolate glaze and let excess cool off.
For the glaze, whisk the sugar and cocoa powder in a shallow bowl. Slowly stir in milk and vanilla extract to make smooth, pourable glaze.
Even though they say non-stick, spray your donut pans with non-stick cooking spray to make sure the donuts come out.
When measuring the flour, lightly spoon it into a measuring cup and then level it off with the back of a knife to get the right amount.
You can spoon the batter into the donut pans, but the easiest way to get the batter in the pan is by using a pastry bag or Ziploc bag with the corner cut off.
Just like with any cake type batter that you make, you'll know the donuts are done when a toothpick comes out clean.
Let the donuts cool completely before you dip them in the glaze.
Leftovers will store well in at room temperature for 1-2 days in an air-tight container.