Prepare and Sear the Beef: Season the chuck roast with rosemary salt and black pepper, then sear in a hot pan with cooking oil.
Sauté Onions and Garlic: In the same pan, sauté onions and garlic, then add tomato paste and cook down.
Build the Sauce: Transfer onions and garlic to a Dutch oven, add flour, then gradually add red wine, beef stock, Worcestershire sauce, balsamic vinegar, and marmite. Bring to a simmer.
Cook the Pot Roast: Add the seared beef to the sauce, cover, and cook in the oven at 325°F for 2 hours.
Add Vegetables: Add carrots and potatoes to the pot and continue cooking for another hour or until tender.
Serve: Let the pot roast rest before serving. Serve with the vegetables and sauce.