Preheat oven to 300 degrees F.
Rub meat with seasoned salt, kosher salt, and pepper. Place meat in a large roasting pan. Add 1-inch of water to the pan. Place carrots, celery, and onions around the meat. Cover meat with foil and place in oven; cook for approximately 4 to 5 hours, or until the internal temperature reaches 140 degrees F when measured on a meat thermometer. Remove from oven and let rest for 10 minutes. Slice it as it is served.