Preheat your oven to 300°F.
Combine dark brown sugar, kosher salt, chili powder, garlic powder, onion powder, and black pepper in a bowl.
Rub the dry mixture all over the pork shoulder, covering every inch.
Let it sit at room temperature for about 30 minutes.
Place the seasoned pork in a roasting pan.
Pour the liquid smoke over it evenly.
Cover the pan tightly with foil.
Roast in the oven for 4 to 5 hours, until the pork is tender and easily pulled apart with a fork.
Remove the pork, shred it with forks, and mix it with your favorite barbecue sauce.
Serve on buns or with coleslaw.