Heat a large Dutch oven over medium-high heat. Rub roast with vegetable oil and season liberally with salt and pepper or Montreal Seasoning. Brown in the hot pan on all sides, 10-12 minutes. Remove from heat.
Bring brine and flavor pouch to a boil in a saucepot or large Dutch oven – I secure mine with kitchen twine to side of pot. Turn heat off and let cool. Combine brine and meat in the pot or in another container and refrigerate 3 days, turning meat occasionally.
To cook, bring meat to room temperature. Sprinkle sugar into the pot and combine with sauce. Preheat oven to 325°F and roast about 3 1/3-4 hours. Meat may also be cooked in a slow cooker on high for 4 hours or low for 7 hours.