French Onion Soup

French Onion Soup

A classic French soup of deeply caramelized onions in rich stock, topped with a baguette and gruyère and broiled until golden. Take your time with the onions and anyone can make it deeply savory.

Ingredients

4servings
  • Onions · large, thinly sliced, ~800g4
  • Butter3 tbsp
  • Olive oil1 tbsp
  • Sugar · to help caramelize, optional1 tsp
  • Flour · to thicken, optional1 tbsp
  • White wine · optional, to deglaze100 ml
  • Beef stock (or vegetable)1 L
  • Thyme · or a little dried2 sprigs
  • Salt & pepper1 to taste
  • Cheese toast
  • Baguette4 slices
  • Gruyère (or Emmental) · grated100 g

Steps

  1. Melt the butter and olive oil in a wide pot, add the sliced onions, and caramelize over medium-low heat 25–35 minutes, stirring often, until deep golden brown (a little sugar helps). Going slow is the key.

    ⏲ 30 min
  2. Stir in the flour and cook 1 minute, then pour in the wine and scrape up the bottom as it reduces.

    ⏲ 2 min
  3. Add the stock and thyme, bring to a boil, then simmer 15–20 minutes. Season with salt and pepper.

    ⏲ 20 min
  4. Lightly toast the baguette slices. Preheat the broiler.

    ⏲ 5 min
  5. Ladle the soup into oven-safe bowls, top with the baguette, and cover generously with cheese.

    ⏲ 2 min
  6. Broil 3–5 minutes until the cheese is melted, golden, and bubbling. Serve hot.

    ⏲ 5 min

Tips & Variations

Variations

  • Vegetarian: Use a rich vegetable stock instead of beef.
  • Cheese blend: Mix gruyère with mozzarella and Parmigiano.
  • Sherry/cognac: A splash at the end adds depth.
  • No bowls: Melt cheese on the toast separately and float it on top.

Tips

  • Don't rush the onions — slow, deep caramelizing is where the sweetness comes from.
  • Deglaze with a little liquid to capture the browned flavor when it sticks.
  • Use a rich stock for deep flavor.
  • Gruyère melts well and is the classic nutty cheese.
  • No oven-safe bowls/broiler? Toast the cheese bread separately and add it on top.

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