Here's what I do:
Slow Roasted Pork Shoulder
1 Ea Pork Butt, 6 to 8 Lb.
C Kosher salt
C Light Brown Sugar
TT Ground Black Pepper
2-3 Tb Flour
Cut slits 1 inch apart in the fat cap of the roast, being careful not to cut into the meat. If the roast is boned, tie it with string to a uniform shape. Combine the salt and brown sugar in a bowl and rub it all over the pork shoulder and into the slits. Wrap the roast tightly in a double layer of plastic wrap, place it on rimmed baking sheet and refrigerate for 12 to 24 hours.
Preheat the oven to 325º F.
Adjust an oven rack to the lowest position in the oven. Unwrap the roast and brush off any excess salt mixture. Season the roast with pepper. Place the roast onto a V-rack coated with nonstick cooking spray set in large roasting pan and add 1 quart of water to the roasting pan.
Cook the roast, basting it twice during cooking, until an instant-read thermometer inserted into the roast, near but not touching any bone, registers 190º F, about 5 to 6 hours. Add water to the pan as needed to prevent its drying out.
Transfer the roast to a carving board and let it rest, loosely tented with foil, for 1 hour prior to carving.
To make a gravy, transfer the liquid in the roasting pan to a fat separator and let it stand.
Using 2-3 tablespoons of fat and an equal amount of flour, make a roux. Whisk in the defatted liquid from the roasting pan supplemented with chicken broth if necessary. Bring it to a boil and simmer for 3-4 minutes to make the gravy.