1. Heat olive oil and butter in a large pot over medium heat. Add the onions and cook, stirring occasionally, until they are caramelized, about 30 minutes. This step requires patience, but trust me, it’s worth it!
2. Add the garlic and cook for another minute until fragrant. Stir in the red wine, scraping up any browned bits from the bottom of the pot.
3. Season the short ribs with salt and pepper. Add them to the pot, nestling them among the onions. Pour in the beef broth, add the bay leaf and thyme, and bring to a simmer.
4. Reduce the heat to low, cover, and let the soup cook for about 2.5 to 3 hours, or until the short ribs are tender and the flavors have melded beautifully.
5. Once the ribs are tender, remove them from the pot, shred the meat, and discard the bones. Return the meat to the soup.
6. Preheat your broiler. Ladle the soup into oven-safe bowls, top with toasted baguette slices, and sprinkle with Gruyère cheese.
7. Place the bowls on a baking sheet and broil until the cheese is bubbly and golden brown, about 2-3 minutes. Watch closely to prevent burning.

This dish is truly a labor of love, reminiscent of the slow, intentional cooking I watched my grandmother do. The key here is patience and allowing the flavors to develop.