Food EditionCookFrenchDinnerFrench Onion Soup
2 hr 30 minIntermediateServes 4
French · Dinner

French Onion Soup

This soup is built on the patience required to caramelize onions until they reach a deep, dark mahogany. You cook the onions low and slow, deglaze with dry vermouth or wine to pull up the browned bits, and finish with a toasted baguette slice buried under a thick layer of melted Gruyère.

Total time
2 hr 30 min
Hands-on
45 min
Serves
4
Difficulty
Intermediate
Before you start

Patience is your primary ingredient.

Do not rush the onions. If you crank the heat to save time, they will burn instead of developing the necessary deep, jammy sweetness.

  • Heavy-bottomed Dutch oven
  • Wooden spoon
  • Oven-safe crocks or bowls
  • Chef's knife
Ingredients

What goes in.

  • 3 lbyellow onions, sliced pole-to-pole into 1/4-inch strips
  • 4 tbspunsalted butter
  • 1 tbspolive oil
  • 1/2 cupdry white wine or dry vermouth
  • 6 cupsrich beef stock
  • 2fresh thyme sprigs
  • 1bay leaf
  • 1/2 loafcrusty baguette, sliced into 1-inch thick rounds
  • 8 ozGruyère cheese, grated
The key technique

Deep Caramelization

The goal is to move the onions through shades of gold into a deep brown without charring. This creates the concentrated base that provides the soup its structure.

Step by step

The method.

  1. Caramelize the onions

    Melt butter and oil in the Dutch oven over medium heat. Add onions and stir to coat. Cook for 45 to 60 minutes, stirring every few minutes, until they are reduced in volume and the color of dark toast.

  2. Deglaze

    Pour in the wine. Use your wooden spoon to scrape the bottom of the pot, lifting the dark, sticky bits (the fond) into the liquid.

  3. Simmer

    Add the stock, thyme, and bay leaf. Bring to a boil, then reduce to a low simmer for 30 minutes. Remove the herbs before serving.

  4. Toast the bread

    While the soup simmers, toast the baguette slices in a 400°F oven until they are crisp and dry to the touch.

  5. Broil

    Ladle soup into oven-safe crocks. Place a toasted baguette slice on top, cover generously with Gruyère, and place under the broiler until the cheese is bubbling and showing brown spots.

Tips & troubleshooting

When it doesn't go to plan.

Tip

If the onions look like they are drying out or catching too quickly, add a tablespoon of water to help them soften.

Tip

Use a beef stock with high gelatin content for a better mouthfeel.

Tip

Slice onions pole-to-pole (root to stem) rather than across the grain; they will hold their shape better during the long cook time.

Questions

The ones that keep coming up.

Can I use a different cheese?

Gruyère is the standard, but Comté or a mix of Emmental and Parmesan works if you want a sharper salt profile.

How do I know the onions are done?

They should look like marmalade and feel completely soft, with a deep, rich brown color throughout.

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