1. Preheat oven to 325º. Heat oil in a 5-quart Dutch oven over medium heat. Add beef and brown on all sides, about 15 minutes; transfer to a platter. Raise heat to medium-high and add potatoes, onions, carrots, and parsnips; cook, stirring, for 10 minutes, or until vegetables are lightly browned on edges. Stir in flour and cook 3 minutes, or lightly browned.
2. Add broth, wine, water, parsley sprigs, brown sugar, bay leaf, garlic, salt, and pepper; bring to a boil.
Return beef and juices to Dutch oven, layering beef between vegetables. Cover with a tight-fitting lid, transfer to oven, and cook for 2 1/2 hours, or until beef is very tender.
3. Transfer roast to a cutting board and let stand for 20 minutes. Cut in half along the grain; reserve one half. Remove vegetables from sauce with a slotted spoon, transfer to a bowl, and toss with 2 tablespoons minced parsley. Discard parsley sprigs and bay leaf. Reserve 5 cups sauce.
4. Allow reserved roast and sauce to come to room temperature. Cover and refrigerate for up to five days.
5. Meanwhile, serve remaining pot roast: Slice against the grain into 1/4-inch thick slices. Arrange in the center of a serving platter with vegetables around the edge. Spoon half the remaining sauce over beef; garnish platter with the rest of the minced parsley. Pass remaining sauce at table.