1. Season the beef with the salt and black pepper.
2. Heat the oil in a 12-inch skillet over medium-high heat. Add the beef and cook until well browned on all sides. Remove the beef from the skillet. Pour off all but 1 tablespoon fat.
3. Add the shallots to the skillet. Cook for 10 minutes or until tender, stirring occasionally. Add the garlic, mushrooms and flour and cook and stir for 1 minute. Stir in the tomatoes.
4. Stir the stock, vinegar and brown sugar in a small bowl until the mixture is smooth. Stir the stock mixture in the skillet and heat to a boil. Return the beef to the skillet. Reduce the heat to low. Cover and cook for 1½ hours.
5. Uncover the skillet and cook for 30 minutes or until the beef is fork-tender and the vegetables are tender.
6. Grate 2 tablespoons zest from the lemon. Stir the lemon zest and parsley in a small bowl. Sprinkle the lemon zest mixture over the beef mixture.