Prepare the Short Ribs: Season short ribs with salt and pepper. In a large pot or Dutch oven, heat olive oil over medium-high heat. Brown short ribs on all sides, about 2–3 minutes per side. Remove and set aside.
Caramelize the Onions: In the same pot, reduce heat to medium and add butter. Sauté onions with a pinch of salt and sugar (if using) for 25–30 minutes until golden brown and caramelized, stirring frequently. Add garlic during the last 2 minutes.
Build the Soup: Return short ribs to the pot. Add beef broth, water, Worcestershire sauce, thyme, and bay leaf. Bring to a boil, then reduce heat and simmer for 2–3 hours until the short ribs are tender and the flavors meld. Remove bay leaf.
Prepare the Bread: Preheat oven to 375°F (190°C). Place baguette slices on a baking sheet and top with shredded cheese. Bake for 5–10 minutes until golden and bubbly.
Serve: Ladle soup into bowls, top with a slice of cheesy bread, and serve hot.
Serving and Storage Tips
