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French Onion Soup

Classic French Onion Soup

French onion soup with slowly caramelized yellow onions, a beef broth base, toasted baguette, and a broiled Gruyère top.
Prep Time: 20 minutes
Cook Time: 1 hour 40 minutes
Total Time: 2 hours
Course: Dinner, Soup
Cuisine: French
Servings: 6 servings

Equipment

Ingredients

  • 4 tbsp unsalted butter
  • 1 tbsp olive oil
  • 3 lbs yellow onions about 5 large, halved and thinly sliced
  • 1 tsp salt
  • 1/2 tsp granulated sugar
  • 2 cloves garlic minced
  • 2 tbsp all-purpose flour
  • 3/4 cup dry white wine
  • 6 cups beef broth
  • 1 tbsp Worcestershire sauce
  • 1 tbsp dry sherry optional
  • 1 tsp fresh thyme leaves or 1/2 tsp dried
  • 2 bay leaves
  • 1/2 tsp black pepper
  • 8 slices baguette 1/2 inch thick
  • 8 oz Gruyère cheese shredded, about 2 cups
  • 1/4 cup grated parmesan

Instructions

  • Slice the onions: Halve the onions through the root end and slice them thinly, about 1/8 inch. Three pounds looks absurd going into the pot and cooks down to roughly 2 cups, so use the biggest Dutch oven you own.
  • Caramelize, slowly: Melt the butter with the olive oil in the Dutch oven over medium heat. Add the onions, salt, and sugar and cook 45-55 minutes, stirring every 5 minutes or so, until they're deep golden brown and jammy. Scrape the brown film off the bottom as it builds. That layer is where most of the flavor lives.
  • Add the garlic and flour: Stir in the garlic and cook 30 seconds. Sprinkle the flour over the onions and stir constantly for 1 minute to cook off the raw taste.
  • Deglaze with wine: Pour in the white wine and scrape the bottom of the pot clean. Simmer 4-5 minutes, until the wine has mostly cooked away and the onions look glossy.
  • Simmer the soup: Add the beef broth, Worcestershire, sherry if using, thyme, bay leaves, and pepper. Bring to a simmer and cook uncovered 30 minutes so the flavors settle. Fish out the bay leaves and taste for salt.
  • Toast the bread: While the soup simmers, arrange the baguette slices on a sheet pan and bake at 400°F for 8-10 minutes, flipping once, until dry and lightly golden. Dry bread is what keeps the top from sinking into the bowl.
  • Broil the cheese and serve: Set oven-safe bowls on a sheet pan and ladle in the hot soup. Float 1-2 baguette slices on each, cover them edge to edge with the Gruyère, and scatter the parmesan on top. Broil 3-5 minutes, until the cheese is melted, bubbling, and browned in spots. Serve right away, and warn everyone the bowls are extremely hot.

Notes

Give the onions the full 45-55 minutes over medium heat and scrape the brown film off the bottom of the pot as it builds, since that fond is most of the flavor. Toast the baguette slices dry so they don't sink, and shred the Gruyère off the block so it melts instead of browning over cold cheese. Reheat leftover soup on the stove to a full simmer, 165°F, before serving.