French Onion Soup

4.86 from 14 votes

Classic French Onion Soup made with caramelized yellow onions, red wine, beef broth, fresh thyme, and baguette toasts topped with melted Gruyère.

Prep Time10

Cook Time50

Total Time1

Course: Soup

Cuisine: French

Servings: People

Author: Gaby Dalkin

Ingredients

¼ cup unsalted butter
5 yellow onions thinly sliced
4 cloves garlic finely chopped
2 bay leaves
3-4 fresh thyme sprigs
Kosher salt and freshly ground black pepper
1 cup red wine
3 tablespoons all-purpose flour
2 quarts beef broth
1 baguette sliced
½ pound grated Gruyère

Instructions

Melt the butter in a large pot over medium heat. Add the onions, garlic, bay leaves, thyme, salt, and pepper, and cook until the onions are very soft and caramelized, about 25 minutes.
Add the wine, bring to a boil, reduce the heat, and simmer until the wine has evaporated and the onions are dry, about 5 minutes. Discard the bay leaves and thyme sprigs.
Dust the onions with flour and give them a stir. Turn the heat down to medium-low so the flour doesn't burn, and cook for 10 minutes to cook out the raw flour taste.
Next, add the beef broth, bring the soup back to a simmer, and cook for 10 minutes. Season to taste with salt and pepper.
Once the soup is done, preheat the broiler. Arrange the baguette slices on a baking sheet in a single layer. Top the toasts with the Gruyère and broil until bubbly and golden brown, 3 to 5 minutes.
Ladle the soup into bowls and float the Gruyère toasts on top.

Notes

Make sure you have soup bowls, ramekins, or mini crocks that are oven-safe. That way you can do the best part of this recipe - broiling the cheese on top!

Take your time caramelizing the onions. This is where the soup develops so much of its flavor. Cook the thinly sliced yellow onions until they're very soft, deeply golden, and caramelized before adding the wine.
Don't crowd the onions into too small a pot. Give them enough room to cook down evenly, so they caramelize rather than simply steam.
Deglaze the pot with the red wine. As the wine cooks down, scrape up the browned bits from the bottom of the pot so all that flavor makes its way into the soup.
Cook the flour before adding the broth. Give it the full 10 minutes called for in the recipe so you don't end up with a raw flour taste in the finished soup.
Use Gruyère if you can. Its nutty, savory flavor and excellent melting quality make it especially good with the sweet caramelized onions and rich beef broth.
Broil the Gruyère toasts separately. Top the baguette slices with cheese and broil until bubbly and golden, then float them on the soup just before serving.
Make the soup ahead and the toasts fresh. French Onion Soup is a great make-ahead recipe. Reheat the soup gently, then make the Gruyère toasts just before serving so they're hot and crisp.

Nutrition (estimated)