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French Onion Soup

French Onion Soup is a comforting dish featuring slow caramelized onions in a rich broth, topped with toasted bread and gooey, browned Gruyère cheese. The key techniques include gentle caramelization and broiling for a bubbly, golden crust, resulting in a warm, deeply flavorful bowl with tender onions and crisp bread. Its final appearance is a bubbling, golden-topped soup that invites cozy, satisfying bites.
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Prep Time 15 minutes
Cook Time 1 hour 15 minutes
Total Time 1 hour 30 minutes
Servings: 4
Course: Main Course
Cuisine: French
Calories: 350
Ingredients Equipment Method Notes

Ingredients
  

  • 4-5 large yellow onions thinly sliced, about 3mm
  • 2 tbsp butter for caramelization
  • 1 tbsp olive oil to help onions cook evenly
  • 0.5 cup dry white wine adds depth and acidity
  • 4 cups beef broth or vegetable broth for lighter flavor
  • 1 sprig fresh thyme for fragrant earthy notes
  • 4 slices baguette or crusty bread toasting for crunch
  • 1.5 cups Gruyère cheese freshly grated for better melt
  • 1 clove garlic for rubbing on toasted bread (optional)

Equipment

  • Large heavy-bottomed pot
  • Sharp knife and chopping board
  • Wooden spoon
  • Oven-safe bowls or crocks
  • Baking sheet

Method
 

  1. Slice the onions thinly and evenly to ensure uniform caramelization. Keep the slices separate and set aside.
  2. Heat the butter and olive oil together in a large heavy-bottomed pot over medium-low heat. Once melted and shimmering, add the sliced onions and stir to coat them evenly. Cook slowly, stirring every 10 minutes, until the onions are deeply golden and jammy, about 45-60 minutes. The onions will emit a sweet, smoky aroma as they caramelize.
  3. After the onions are beautifully caramelized, pour in the white wine and turn the heat up to medium. Let the wine simmer and reduce by half, scraping up any browned bits from the bottom of the pot. This step adds depth and enhances flavor.
  4. Add the beef broth and a sprig of thyme to the pot. Bring the mixture to a gentle simmer, then reduce the heat to low. Cover loosely and cook for another 15 minutes, allowing the flavors to meld together.
  5. Preheat your oven's broiler to high. Meanwhile, slice the baguette into 1cm thick rounds. Toast the bread slices under the broiler until golden and crisp, about 1-2 minutes per side. Rub the toasted slices with the cut side of garlic for added aroma if desired.
  6. Remove the thyme sprig from the soup. Ladle the hot soup into oven-safe bowls or crocks. Top each with a toasted bread slice, then generously sprinkle grated Gruyère cheese over the bread.
  7. Place the bowls on a baking sheet and broil in the oven for 3-5 minutes until the cheese is bubbly, golden, and slightly browned. Keep a close eye to prevent burning. The cheese should be gooey and crispy at the edges.
  8. Carefully remove the bowls from the oven. Let them sit for 2 minutes to allow the cheese to set slightly. Serve immediately, enjoying the bubbling, cheesy top and tender caramelized onions beneath.

Notes

Patience during caramelization is key for deep flavor. Use freshly grated Gruyère for melting perfection. Toast the bread until crisp for the best texture contrast. Serve immediately for optimal gooey cheese and warm broth.