Cooking Steps

• Arrange a rack in center of oven; preheat to 325°. Pat beef dry with paper towels. Using a spice grinder, pulse or crush onion soup mix, pepper, and 1 Tbsp. salt until large pieces are broken down. Season beef all over with seasoning mix.
• In a large skillet over medium heat, heat 1 Tbsp. oil. Cook beef until just starting to brown, 3 to 4 minutes per side. Transfer to a plate.
• In the same skillet, heat remaining 1 Tbsp. oil. Add onions and season with remaining ½ tsp. salt. Cook until onions brown, about 10 minutes. Add wine and cook until slightly reduced, 2 to 3 minutes. Pour in broth and add beef back. Add thyme and bring to a simmer. Cover and transfer to oven.
• Roast beef, turning halfway through, until meat easily pulls apart with a fork, 2 hours and 45 minutes to 3 hours.
• Transfer beef to a cutting board. Remove and discard thyme. Return skillet to medium heat and bring sauce to a simmer. Cook until liquid is reduced by about half, about 15 minutes. Shred beef and return to skillet.
• Preheat broiler to high. Top skillet with cheese. Broil until cheese is melted and browned in spots, about 5 minutes.
• Top with more thyme and serve with sliced baguette.