Preheat the oven to 225°F. Season the top round roast liberally with sea salt and crushed peppercorns.
Place the wire rack in the center of the roasting pan then place the roast on it. Roast for 1 hour and 30 minutes or until an instant-read thermometer reaches 130-135°F.
Carefully remove the roast from the oven and drizzle both sides with olive oil. Broil for 2-3 minutes per side to crisp then transfer it to a cutting board.
Increase oven temperature to 450°F to preheat. Meanwhile, arrange the carrots, onion, celery, and garlic on a large sheet pan. Drizzle with olive oil, salt, and pepper to taste. Roast for 20-25 minutes.
Prepare McCormick® Brown Gravy Mix by whisking 2 cups of water with 2 packets of gravy in a small saucepan over medium heat stirring frequently. Once the gravy comes to a boil, reduce the heat and to low and simmer for 1 minute.
Slice the roast and serve with the roasted vegetables and gravy.