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French Onion Soup

A classic French onion soup built on deeply caramelized onions and a rich beef broth, finished with a broiled Gruyère-topped baguette crouton.
Print Recipe
Prep Time 20 minutes
Cook Time 1 hour 30 minutes
Servings: 6
Calories: 385
Ingredients Method

Ingredients
  

  • For the Soup Base
  • 2.5 lbs yellow onions about 6 large, thinly sliced
  • 4 tbsp unsalted butter
  • 1 tbsp olive oil
  • 1 tsp kosher salt divided
  • 1/2 tsp sugar optional
  • 2 cloves garlic minced
  • 2 tbsp all-purpose flour
  • 8 cups beef stock
  • 2 tbsp Worcestershire sauce
  • 2 sprigs fresh thyme or 1/2 tsp dried
  • 1 bay leaf
  • 1/4 cup apple cider vinegar mixed with 2 tbsp water
  • Freshly ground black pepper to taste
  • For the Cheese Toast
  • 1 baguette sliced into 1-inch rounds
  • 8 oz Gruyère cheese grated
  • 2 tbsp grated Parmesan optional

Method
 

  1. Slice the onions uniformly, about 1/8 inch thick.
  2. Melt butter and olive oil in a heavy pot over medium heat; add onions and 1/2 tsp salt.
  3. Cook uncovered 45–60 minutes, stirring every 5–10 minutes, until deep mahogany brown.
  4. Stir in garlic and flour; cook 1–2 minutes.
  5. Deglaze with the vinegar-water mixture, scraping up all the browned fond.
  6. Add beef stock, Worcestershire, thyme, bay leaf, remaining salt, and pepper. Simmer uncovered 30 minutes.
  7. Remove thyme and bay leaf; taste and adjust salt.
  8. Ladle into oven-safe bowls, top with baguette and Gruyère, and broil 2–4 minutes until browned and bubbling.
  9. Rest 5 minutes before serving.