Preheat the oven to 350°F. Grease a donut mold and set aside.
In a medium mixing bowl, whisk together the flour, corn starch, baking powder, spices, and salt.
In a large mixing bowl, combine the melted butter, pumpkin puree, eggs, and brown sugar.
Add the flour mixture to the wet ingredients and fold in until combined. Dough will be thick.
Scoop the dough into a piping bag with a large opening.
Pipe the donut batter into the the donut mold and set aside.
In a small mixing bowl, whisk together the flour, cinnamon, melted butter, and brown sugar to form the streusel.
Generously sprinkle the streusel over the donuts, lightly pressing it down so it adheres to the donut during baking.
Bake the donuts for 10-12 minutes or until golden brown.
While the donuts cool, mix the powdered sugar and milk to create the glaze.
Drizzle the donuts with the glaze once they have cooled.
Enjoy!
Notes
When baking homemade donuts in a silicone baking pan, it's important to let them cool in the pan for a few minutes before trying to remove them. This allows the donuts to set and firm up a bit, making it easier to release them from the pan without breaking them.
You can add the glaze to the hot donuts to eat them warm, however the glaze will be runnier from the heat of the donut.