When writing this, it is 30 degrees in Austin, TX and that means it is the perfect time for soup! If you're craving a rich, cozy bowl of french onion soup, this is the recipe you need.

Ingredients
4 pounds yellow onions, peeled and thinly sliced (approximately 5–6 large onions)
3 tablespoons butter
4 cloves garlic, minced
3 tablespoons flour
1/2 cup dry white wine
6 cups of beef stock (or veggie stock)
1 teaspoon Worcestershire sauce
1 bay leaf
3 sprigs fresh thyme (or 1 teaspoon dried thyme)
Sea salt and pepper
Baguette
Grated or sliced cheese (such as Gruyere, Asiago, Swiss, or Gouda)
Instructions
In a large heavy-bottomed pot, melt the butter over medium-high heat. Add the onions and sauté until well for about 30 minutes until caramelized (but not burnt), initially stirring every 3-5 minutes, then about once a minute near the end of caramelization to prevent burning. (Yes, it will look like a crazy amount of onions in the pot and will take longer than you think!)
Add garlic and sauté for 2 minutes.
Stir in the flour and cook for an additional 1 minute.
Stir in the wine to deglaze the pan, using a wooden spoon to scrape up any browned bits on the bottom of the pan.
Add the stock, Worcestershire, bay leaf, and thyme and stir to combine. Continue to cook until the soup reaches a simmer. Then reduce heat to medium-low, cover and simmer for at least 10 minutes.
Discard the bay leaf and sprigs of thyme. Taste the soup and season with salt and pepper as needed.
Preheat oven to 400°F. While the soup is simmering, slice the baguette into 1-inch thick pieces and arrange them in single layer on baking sheet. Bake for 6-8 minutes, until the bread is toasted and golden around the edges. Remove and set aside.
Switch the oven to the broiler. Once the soup is ready to serve, place oven safe bowls on a thick baking sheet. Ladle the soup into each bowl, then top with a baguette slice and your desired amount of cheese. Place on an oven rack about 6 inches from the heat and broil for 2-4 minutes, or until the cheese is melted and bubbly. (Watch them closely so they do not burn!)
Remove from the oven and serve immediately.
Notes
Oven-safe bowls: Double-check the maximum temperature for any bowls that you place in the oven. Many are not safe for broiling!
Here are two I recommend:
Made this last night - SO GOOD!!! I used a blend of cheeses you recommended and it was perfect.