I use about 4 pounds of small pie pumpkins, cut into wedges (about 8 wedges per pumpkin), with the stems and seeds removed. Place these in a roasting pan with about a cup of water; this will keep the pumpkin from burning while roasting.
Roast pumpkin at 450F for 15 minutes, then lower oven temp to 350F and roast until tender. Deglaze roasting pan w/2 cups water and reserve. Add warm pumpkin to mash, along with 1-2 pounds of rice hulls to avoid stuck sparge.
In the boil, I actually used 12.75 ounces of maple syrup, not brown sugar, but BrewToad doesn't have that ingredient yet.
Also, I used Calypso hops (12.8% AA) and not Chinook, but BrewToad doesn't have Calypso yet.
Add the reserved pumpkin-flavored jus immediately after flameout.
Cool, pitch, and ferment at 68F.
After primary fermentation, rack to secondary and add the following spices:
half an ounce of cinnamon stick, broken into pieces
2 vanilla beans, roughly chopped
1 tsp ground nutmeg
1 tsp ground cloves
1 tsp ground allspice
1/2 tsp ground ginger
"Dry spice" for at least a week. Carbonate to 2.2 volumes CO2, and condition for at least 2 weeks prior to drinking. This is a big beer that will improve with age.