Creating this amazing French Onion Soup is simple when you follow these steps:

1. Melt Butter and Oil: In a large stockpot or Dutch oven, melt the butter and olive oil over medium heat.

2. Caramelize Onions: Add the sliced onions, salt, and sugar. Cook them, stirring frequently for about 25-30 minutes, or until they turn a deep golden brown.

3. Add Garlic: When the onions are well-caramelized, stir in the minced garlic and cook for an additional 1-2 minutes until fragrant.

4. Deglaze the Pot: Add the white wine and scrape the bottom of the pot with a wooden spoon to remove any browned bits. Allow the wine to simmer for about 3-4 minutes until reduced.

5. Add Broth and Herbs: Pour in the beef broth, thyme, bay leaf, and season with black pepper. Bring the mixture to a gentle simmer, then reduce the heat to low. Let it cook for an additional 20 minutes to meld the flavors.

6. Prepare the Bread: While the soup is simmers, preheat your oven to 400°F (200°C). Place the baguette slices on a baking sheet and toast them in the oven for about 5-7 minutes, until golden brown and crispy.

7. Remove Bay Leaf: Before serving, remove the bay leaf from the soup.

8. Assemble the Soup: Ladle the hot soup into oven-safe bowls, placing a few slices of toasted baguette on top of each bowl.

9. Add Cheese: Generously sprinkle the Gruyère and Parmesan cheeses over the bread in each bowl.

10. Broil: Place the bowls in the oven and broil them for about 2-3 minutes, or until the cheese is melted and bubbly. Monitor closely to avoid burning.