INSTRUCTIONS

1. For the stew, position rack in bottom third of oven. Preheat to 325°F.
2. Pat beef dry with paper towel. Season with 1 ¼ tsp salt. Heat oil in a large, ovenproof pot over medium-high. Add half the beef. Cook, turning occasionally, until browned on all sides, approximately 10 to 14 minutes. Transfer to a large plate. Repeat with remaining beef.
3. Discard fat from the pot, then return to medium heat. Add butter. Once melted, add onions and garlic. Season with remaining ½ tsp salt and pepper. Cook, stirring often, scraping brown bits from the bottom of the pot, until onions are very soft and golden, about 7 to 9 minutes. Stir in flour and tomato paste to coat. Cook for 2 minutes. Stir in red wine until combined, then the beef broth. Bring to a full, rapid boil over high heat for 3 minutes. Return beef to the pot (with any juices) and stir in mustard. Return to a boil, then cover with lid. Transfer to bottom third of oven. Cook until beef is just tender, 2 hours.
4. Cut each carrot crosswise in half on the bias, then cut again lengthwise in half. Remove stew from oven, then stir in carrots. Cover, then return to bottom third of oven. Continue cooking until beef is very tender, and carrots are cooked through, about 25 to 30 minutes.
5. For the relish, combine parsley with cornichons and chives in a small bowl. Set aside.
6. To serve, serve relish spooned over stew. Serve alongside crusty bread.