Preheat oven to 325°F and line a baking sheet with parchment paper.
Pour 3 tablespoons of the olive oil in the prepared baking sheet and spoon the prepared vegetables and the unpeeled garlic into the fat. Make sure they are well coated and bake for 25-30 minutes, turning them over at half time so that they roast evenly. When the vegetables are nicely tinged brown at the edges, remove them from the oven and set aside.
While they are in the oven, pat meat dry and rub the joint all over with the remaining tablespoon of olive oil, some crushed sea salt and coarsely ground black pepper. Add garlic, thyme, and rosemary and brown meat on all sides, about 10 minutes total.
Pour in the Beaujolais and baste the meat with it. As soon as the wine begins to bubble, turn off the heat and cover the whole tin with a tent of foil (without it touching the meat). Fold the foil tight under the rim of the tin and replace it in the oven and let it continue cooking for 1½ hours.
Carefully remove the foil and baste the meat well with the wine. Spoon the browned vegetables all around in the wine, season them with salt and freshly milled black pepper and pop in the sprigs of thyme and rosemary and the bay leaf. When it has come back to a simmering point, replace the foil and cook for a further 1½ hours.
Transfer meat to a cutting board. Discard herb stems and boil sauce until reduced by about one third, about 5 minutes, then season with salt.
Cut meat across the grain into 1/2-inch-thick slices. Sprinkle the beef and vegetables with the parsley or thyme, drizzle with sauce and serve.