Now that you have your ingredients ready, let’s dive into the steps for making this delightful French Onion Soup. It’s as easy as pie, and I promise you’ll feel like a culinary superstar!

Step 1: The Sacred Act of Caramelizing the Onions
This is the most critical step and cannot be rushed. In a large, heavy-bottomed Dutch oven or pot, melt the butter and olive oil over medium-low heat. Add the thinly sliced onions and stir to coat. Season with a teaspoon of salt and the optional sugar. Cook slowly, stirring every 10-15 minutes, for at least 45 minutes to 1 hour. They will first wilt, then slowly turn golden, and finally become a deep, rich, mahogany brown. This patience is the soul of the soup.

Step 2: Build the Flavor Base
Once the onions are deeply caramelized, add the minced garlic and cook for one more minute until fragrant. Sprinkle the flour over the onions and stir constantly for 2 minutes to cook out the raw flour taste. This will help thicken the soup.

Step 3: Deglaze with Wine
Pour in the white wine, scraping the bottom of the pot with a wooden spoon to release all the flavorful browned bits (the fond). Let the wine simmer and reduce by about half, which will take 3-5 minutes.

Step 4: Add Broth and Simmer
Add the beef broth, water, Worcestershire sauce, bay leaves, and thyme sprigs. Bring to a boil, then immediately reduce the heat to low, cover, and let it simmer gently for at least 30 minutes (45 is better). This allows the flavors to meld beautifully. Season to taste with salt and pepper. If using, stir in the brandy or sherry at the very end.

Step 5: Prepare the Bread and Cheese
While the soup simmers, preheat your oven to 400°F (200°C). Arrange the baguette slices on a baking sheet, brush with olive oil, and bake for 5-7 minutes per side until golden and crisp. Rub one side of each toast with the peeled garlic clove while still warm. Set your oven to broil. Place your oven-safe soup crocks on a sturdy baking sheet.

Step 6: Assemble the Gratinée
Ladle the hot soup into the oven-safe crocks, filling them nearly to the top. Place 1-2 garlic toasts on the surface of the soup in each crock, pressing down slightly so it absorbs some broth. Generously pile the grated Gruyère and Parmesan over the bread and the edges of the crock.

Step 7: The Grand Finale – Broil to Perfection
Carefully place the baking sheet with the filled crocks under the broiler. Broil for 2-4 minutes, watching CLOSELY, until the cheese is completely melted, bubbly, and spectacularly spotted with golden brown. Remove with care, as the crocks will be extremely hot.

Step 8: Serve with Caution and Joy
Let the soup rest for a few minutes before serving, it is molten lava hot. Serve immediately, warning your guests of the temperature, and enjoy the theatrical, stringy, glorious first bite.