Preheat the Oven: Preheat the oven to 325°F.
Season and Flour the Roast: Place the beef chuck roast in the bottom of a large oven-safe Dutch oven. Season it with salt and black pepper, then rub the flour evenly over the roast to coat it.
Add the Aromatics and Vegetables: Arrange the thinly sliced onion, chopped garlic, and largely chopped carrots around the roast.
Prepare the Wine Mixture: Stir the tomato paste into the 2 cups of red wine until combined.
Build the Braise: Pour the red-wine and tomato-paste mixture over the roast. Add the brandy or cognac, broth, bay leaves, and fresh thyme to the Dutch oven.
Add the Potatoes: Arrange the small to medium potatoes around the roast in the Dutch oven.
Braise the Roast: Cover the Dutch oven and place it in the 325°F oven. Roast for 3 1/2 to 5 hours, or until the beef is very tender.
Increase the Oven Temperature: Raise the oven temperature to 425°F once the initial braising is complete.
Prepare the Mashed Potatoes: Remove the potatoes from the Dutch oven and place them in a bowl. Add the salted butter, room-temperature milk or cream cheese, garlic powder, salt, and black pepper. Mash until well combined. The original method leaves the potato skins on; season the mashed potatoes with additional salt and pepper as needed. Caramelize the Roast: Return the roast to the oven uncovered at 425°F and cook for 20 minutes, until the top is deeply caramelized.
Maintain the Braising Liquid: If needed during the final cooking stage, add additional broth or wine so the onions remain just barely covered.
Finish and Serve: Serve the pot roast topped with flaky sea salt, gravy, and carrots, with the mashed potatoes served alongside. Garnish with the fresh parsley and enjoy.