French Onion Soup

Here is a classic recipe for French Onion Soup, along with tips to ensure you get that deeply flavorful broth and perfectly melted, cheesy topping.

This soup is all about patience, especially when caramelizing the onions.

The King of Comfort: French Onion Soup

This recipe transforms humble onions and broth into a rich, savory, and deeply satisfying dish, finished with a golden, gooey cheese crouton.

Ingredients

· For the Soup:
· 4 tablespoons (55g) unsalted butter
· 2 tablespoons olive oil
· 4 large yellow or sweet onions (about 2.5-3 lbs), thinly sliced pole-to-pole
· 1 teaspoon salt (plus more to taste)
· 1/2 teaspoon sugar (helps with caramelization)
· 8 cups (about 2 liters) beef broth (high-quality, preferably low-sodium)
· 1/2 cup dry white wine or dry vermouth (optional, but recommended)
· 1 tablespoon all-purpose flour (optional, for a slightly thicker texture)
· 2 sprigs fresh thyme (or 1/2 tsp dried thyme)
· 1 bay leaf
· Freshly ground black pepper, to taste
· For the Topping:
· 1 baguette, sliced into 1-inch thick rounds
· 1-2 cloves garlic, peeled
· 2 cups (about 200g) grated Gruyère cheese (or a mix of Gruyère and Comté)
· 1/2 cup (about 50g) grated Parmesan cheese

Instructions

Step 1: Caramelize the Onions (The Most Important Step)

1. In a large, heavy-bottomed pot (like a Dutch oven), melt the butter and olive oil over medium heat.
2. Add the sliced onions, salt, and sugar. Stir to coat the onions in the fat.
3. Cook, stirring occasionally, for about 10 minutes until the onions soften and become translucent.
4. Reduce the heat to medium-low. This is where patience begins. Continue to cook for 40-60 minutes, stirring every 5-10 minutes. You want the onions to turn a deep, rich brown color. If they start to stick or burn, add a tablespoon of water to deglaze the pan and scrape up the brown bits. They should smell sweet and jammy.

Step 2: Build the Broth

1. Once the onions are beautifully caramelized, if using flour, sprinkle it over the onions. Stir and cook for 2-3 minutes to cook out the raw flour taste. (This step helps thicken the soup slightly).
2. If using wine, pour it in and increase the heat to medium-high. Scrape the bottom of the pot with a wooden spoon to lift all the flavorful browned bits (this is called “deglazing”). Let the wine reduce by about half, 2-3 minutes.
3. Add the beef broth, thyme sprigs, and bay leaf. Bring to a boil, then reduce the heat to low.
4. Partially cover and let it simmer for at least 30 minutes (longer is better—up to an hour). This allows the flavors to meld.
5. Remove the thyme sprigs and bay leaf. Season with salt and pepper to taste.

Step 3: Prepare the Croutons

1. While the soup simmers, preheat your oven to 400°F (200°C).
2. Place the baguette slices on a baking sheet. Toast in the oven for 5-7 minutes until dry and lightly golden.
3. Remove from the oven and rub each toast with the cut side of the raw garlic clove. Set aside.

Step 4: Assemble and Broil

1. Preheat your oven’s broiler.
2. Ladle the hot soup into oven-safe bowls or ramekins. Place them on a sturdy baking sheet for easier handling.
3. Place one or two of the garlic-rubbed toasts on top of the soup, making sure they float.
4. Generously pile the grated Gruyère and Parmesan cheese over the toast and right to the edges of the bowl (this creates the famous seal that keeps the bread from getting soggy too quickly).
5. Place the baking sheet with the bowls under the broiler. Broil for 2-4 minutes, watching very carefully, until the cheese is bubbly and deeply browned in spots.
6. Carefully remove from the oven (the bowls will be scorching hot!) and let cool for a few minutes before serving.

Tips for Success

· The Onions: Yellow or sweet onions are best. Slice them from root to stem (pole-to-pole) rather than in rings; they hold their shape better during the long cooking.
· Don’t Rush the Caramelization: This is non-negotiable. A deep caramelization is what gives the soup its signature color and sweet, savory flavor.
· Broth Quality: Since the broth is a primary ingredient, use a good quality one. Homemade beef broth is incredible here, but a good store-bought brand works perfectly.
· The Cheese: Gruyère is the classic choice for its nutty flavor and excellent melting qualities. Don’t skip it!

Enjoy your rich, warming bowl of French Onion Soup