Creating French Onion Beef Short Rib Soup is simple when you follow these steps:

1. Brown the Short Ribs: In a large pot, heat 1 tablespoon of olive oil over medium-high heat. Season the short ribs with salt and pepper. Sear the short ribs on all sides until browned. Remove and set aside.
2. Cook the Onions: Add the remaining olive oil and butter to the pot. Add the sliced onions and cook over medium-low heat, stirring occasionally, until caramelized (about 30-40 minutes). This slow cooking develops the wonderful sweetness of the onions.
3. Add Garlic: Stir in the minced garlic and cook for an additional minute until fragrant.
4. Deglaze the Pot: Pour in the white wine, scraping up any browned bits from the bottom of the pot. Allow the wine to reduce for about 5 minutes.
5. Combine Ingredients: Add the beef broth, thyme sprigs, bay leaf, and the seared short ribs back into the pot. Bring to a boil, then reduce the heat to low and let it simmer for about 1.5 hours.
6. Check the Beef: After 1.5 hours, the beef should be tender and easily fall-off-the-bone. Remove short ribs and let them cool slightly before shredding the meat. Discard any bones and return shredded beef to the pot.
7. Season to Taste: Taste the soup and adjust seasoning with more salt and pepper if needed.
8. Prepare the Bread: Meanwhile, preheat the oven to 400°F (200°C). Toast baguette slices on a baking sheet for about 5-7 minutes until golden brown.
9. Melt the Cheese: Assemble the soup into oven-safe bowls. Top each bowl with a toasted baguette slice and a generous amount of Gruyère and Parmesan cheese.
10. Broil: Place the bowls under the broiler for 2-4 minutes, or until the cheese is bubbly and golden brown. Keep an eye on it to avoid burning!

These steps will guide you in creating this incredible soup, bringing the warm comfort of classic French flavors right to your dining table.