Preheat your oven to 325°F (165°C). Place the chuck roast in a large, oven-safe Dutch oven. Season the roast generously with salt and black pepper, then lightly coat it with flour on all sides.

Arrange the sliced onions, chopped garlic, and carrots around the roast. In a small bowl, mix the tomato paste with 1/2 cup of broth and the balsamic vinegar, then pour this mixture over the meat. Add the remaining broth, bay leaves, and thyme. Place the potatoes around the roast. Cover the Dutch oven with a tight-fitting lid.

Transfer the pot to the oven and roast for 3 1/2 to 5 hours, or until the beef is tender and easily shredded with a fork.

Once the roast is tender, increase the oven temperature to 425°F (220°C). Remove the potatoes from the pot and transfer them to a bowl. Add butter, milk or cream cheese, garlic powder, and a pinch of sea salt. Mash until creamy, leaving the skins on if preferred. Adjust seasoning to taste.

While preparing the potatoes, uncover the roast and return it to the oven. Roast for an additional 20 minutes, allowing the top to caramelize and develop a rich crust. Add extra broth as needed to keep the onions and vegetables moist.

Place the pot roast on a serving platter and spoon the onions, carrots, and savory gravy over the top. Sprinkle with chopped parsley and a pinch of flaky sea salt. Serve the mashed potatoes on the side for a comforting, hearty meal. Enjoy!