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French Onion Soup

French onion soup with deeply caramelized, jammy onions and a rich beef broth, finished with a golden, broiled cheese-crusted baguette topping. The onions cook low and slow for maximum flavor, then the soup simmers and broils until bubbly.
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Prep Time 15 minutes
Cook Time 1 hour 30 minutes
Total Time 1 hour 45 minutes
Servings: 6 servings
Course: Main Dish
Cuisine: French
Calories: 520
Ingredients Equipment Method Notes

Ingredients
  

Yellow onions
  • 4 lb yellow onions Thinly sliced.
Onion cooking fat
  • 4 tbsp unsalted butter
  • 1 tbsp olive oil
Wine for deglazing
  • 1 cup dry white wine or sherry
Beef broth base
  • 6 cup beef broth
Herbs and seasoning
  • 2 fresh thyme Sprigs.
  • 1 bay leaf
  • 1 tsp Worcestershire sauce
  • 0.5 tsp salt Plus more to taste.
  • pepper To taste.
Bread topping
  • 6 baguette or French bread Slices, toasted.
Cheese topping
  • 2 cup Gruyere cheese Shredded.
  • 0.5 cup parmesan Grated.

Equipment

  • 1 Dutch oven

Method
 

Caramelize the onions
  1. Melt the butter with the olive oil in a large heavy pot over medium heat, then add the sliced onions and 1/2 teaspoon salt. Stir to coat so the onions start softening right away (visual cue: glossy onions beginning to sweat).
  2. Cook the onions for 60-70 minutes, stirring every 10-15 minutes, until deeply golden, jammy, and caramelized. Keep the heat at medium so the onions caramelize slowly rather than burn (visual cue: thick, dark-gold onion strands and a jam-like texture).
Build the soup
  1. Deglaze with the wine or sherry, then cook for 3 minutes while scraping up all browned bits from the bottom. Continue until the liquid looks slightly reduced (visual cue: dark fond dissolving into the liquid).
  2. Add the beef broth, fresh thyme, bay leaf, and Worcestershire sauce, then bring to a simmer. Reduce to a steady simmer and cook 20 minutes (visual cue: gentle bubbles around the edges, not a hard boil).
  3. Remove the thyme and bay leaf, then season with salt and pepper to taste. Taste and adjust before ladling (visual cue: well-balanced broth that tastes rich and savory).
Broil the cheese topping
  1. Ladle the soup into oven-safe crocks, then float the toasted baguette slices on top. Arrange so the bread is mostly covered by broth (visual cue: bread sits like a raft on the surface).
  2. Pile the Gruyere and parmesan over the bread, then broil for 3-4 minutes until melted and bubbly. Watch closely so the cheese turns golden-brown with blistered spots (visual cue: bubbling, browned cheese crust).

Notes

Pro tip: caramelize the onions with patience—stirting every 10-15 minutes helps them go jammy instead of scorching. Store leftovers in the fridge up to 3 days; reheat gently on the stovetop and broil fresh cheese/bread topping if you want the best crust. Freezing is not recommended for the final broiled texture. For a lighter option, use reduced-sodium beef broth and reduce the parmesan slightly to cut salt while keeping the onion depth.