Bring roast to room temperature. Rinse well and pat dry. Drizzle with canola oil (not olive oil) and sprinkle salt, pepper, and additional spices generously on both sides of the roast. Rub seasoning into meat until evenly coated.

Preheat oven to 200 degrees Fahrenheit (95 degrees Celsius). In an eight-quart pot, heat two tablespoons of canola oil until almost smoking. Sear meat in hot oil for two to three minutes on each side. Place a roasting rack in a large baking pan and place the seared meat on the rack, fattier side up. Drizzle soy sauce over the roast and place pan in the oven, uncovered.

Roast for about five and a half to six hours, or until the internal temperature of the meat reaches 140°F (60°C) for medium doneness. It will still be slightly pink in the center of the meat, which is what you are looking for.

Remove meat from oven, and loosely tent with foil to rest for 25–30 minutes before slicing. This will allow the meat temperature to rise another five degrees to the perfect doneness. Transfer the meat to a cutting board when it’s finished resting and slice against the grain.

To make the gravy: While the meat is resting, place diced onion in a medium saucepan and sauté in oil until brown and caramelized. Add mushrooms and continue cooking until soft. Once you’ve transferred the meat to the cutting board, deglaze the baking pan with red wine and warm water. Pour the meat drippings into the mushroom and onions, scraping all the little browned bits into the sauce, to impart lots of meaty flavor. Add thyme and cornstarch slurry and bring to a low boil, stirring until slightly thickened.

Spoon gravy over meat and serve immediately.