Preheat the oven to 180 degrees C. Heat 1 tablespoon of the oil in a flameproof casserole dish, add the beef and cook over medium-high heat for 4–5 minutes or until browned all over. Transfer the meat and its juices to a plate.
Add the remaining 1 tablespoon oil to the pan and reduce the heat to low, then add the onion, carrots, parsnip and garlic. Cook, stirring frequently, for 5 minutes. Return the beef and its juices to the pan together with the stout, stock, mixed herbs, vinegar, mustard and sugar. Stir well and bring to the boil. Cover the casserole and transfer to the oven. Cook for 2 hours or until the beef is tender.
Meanwhile, to make the garlic bread, cut baguette into 8 thick slices. Mix together the garlic, parsley, thyme and oil and spoon evenly over one side of each slice of bread.
Uncover the casserole and add pepper to season. Lay the slices of bread, oiled side up, in a circle around the edge of the casserole dish, overlapping them slightly. Return the casserole to the oven to cook for 20–30 minutes or until the bread is golden and crisp. Serve hot.