Classic French Onion Soup (Printable version)

Deeply caramelized onions in savory broth, topped with toasted bread and melted Gruyère cheese.

# Ingredient list:

→ Onions

01 - 3 large yellow onions, thinly sliced
02 - 1 tablespoon unsalted butter
03 - 1 tablespoon olive oil

→ Soup Base

04 - 2 cloves garlic, minced
05 - 1 teaspoon sugar
06 - 1/2 teaspoon salt
07 - 1/4 teaspoon freshly ground black pepper
08 - 2 tablespoons all-purpose flour
09 - 1/2 cup dry white wine
10 - 5 cups beef or vegetable stock
11 - 2 sprigs fresh thyme
12 - 1 bay leaf

→ Topping

13 - 4 slices French baguette, about 1 inch thick
14 - 1 tablespoon olive oil for bread
15 - 1 cup Gruyère cheese, grated

# Step-by-step guide:

01 - Heat butter and olive oil in a large pot or Dutch oven over medium heat. Add sliced onions and stir to coat. Cook, stirring frequently, until onions are soft and deeply caramelized, about 35 to 40 minutes. Add sugar and salt halfway through cooking to promote caramelization.
02 - Add minced garlic to the caramelized onions and cook for 1 minute until fragrant.
03 - Sprinkle flour over the mixture and cook, stirring constantly, for 2 minutes to develop a light roux.
04 - Pour dry white wine into the pot while scraping the bottom with a wooden spoon to release all browned bits and caramelized flavor.
05 - Pour in the stock and add thyme sprigs and bay leaf. Bring to a simmer, then reduce heat and cook uncovered for 20 to 25 minutes. Remove thyme and bay leaf. Season with black pepper and additional salt to taste.
06 - Preheat oven broiler. Arrange baguette slices on a baking sheet, brush both sides with olive oil, and toast under the broiler until golden, about 1 to 2 minutes per side.
07 - Ladle hot soup into oven-safe bowls. Top each with a toasted baguette slice and cover generously with grated Gruyère cheese.
08 - Place filled bowls on a baking sheet and broil for 2 to 3 minutes until cheese is melted, bubbly, and golden brown. Serve immediately.

# Expert tips:

01 -
  • The onions caramelize into something so sweet and deep you will wonder why you ever rushed them before.
  • That first bite through the melted cheese and soaked bread is like breaking through a golden crust into pure comfort.
  • It looks fancy enough for guests but forgiving enough that even a distracted cook can nail it.
  • Leftovers somehow taste even better the next day when all the flavors have had time to become friends.
02 -
  • If your onions are not caramelizing, your heat is probably too low or you are stirring too often, let them sit and develop some color before you move them around.
  • Use oven-safe bowls or ramekins for the broiling step, regular bowls can crack under high heat and nobody wants that mess.
  • Do not skip deglazing with wine, those stuck-on bits are the soul of the soup and water will not lift them the same way.
03 -
  • Add a splash of brandy or sherry along with the wine for a deeper, more complex flavor that tastes like you went to culinary school.
  • If you want an even richer soup, stir in a tablespoon of butter at the very end just before ladling it into bowls.
  • Use a mandoline to slice the onions if you have one, it keeps them uniform so they cook evenly and saves your fingers from all that chopping.
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