Preheat the oven to 350°F with a rack in the center position.

Generously season the beef all over with the salt and pepper. Heat the olive oil in a Dutch oven over medium-high heat. Once the oil just begins to smoke, working in batches, add the meat and cook until browned, 2 to 3 minutes per side. Transfer the meat to a plate.

Reduce the heat to medium. Add the pancetta and cook, stirring occasionally, until it crisps and the fat has rendered, 3 to 4 minutes. Add the onion, carrots, and celery, and cook, stirring constantly, until softened, about 5 minutes. If the vegetables are sticking to the bottom of the pot, add a bit of water and scrape up the browned bits. Add the garlic and cook, stirring, until fragrant, about 1 more minute. Stir in the tomato paste to combine. Pour in the wine and stir to incorporate.

Return the meat to the pan along with any collected juices, nestling it in but not submerging it. Add the bay leaves and thyme. Increase the heat to high and bring to a boil, then cover the pot and transfer it to the oven. Cook for about 2 hours, or until the meat is tender and shreds easily with a fork. Discard the bay leaves and thyme stems. Using tongs, transfer the meat to a serving platter and tent with foil to keep warm.

Return the pan to medium-high heat and bring the liquid to a boil. Cook until reduced by about a third, 8 to 10 minutes. Pour the sauce over the meat on the platter. Garnish with parsley.

Serve the pot roast family-style with mashed potatoes or egg noodles alongside.