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French onion soup

Traditional French onion soup with toasted toast. Humble ingredients - onions, stock, bread, and cheese become luxurious through patient caramelization and a quick gratin under the broiler. The essence is sweet-savory depth balanced with a touch of acidity.

Ingredients:

  • 7 peeled and sliced onion
  • 20 g / 0,7 oz / 0,1 cup butter
  • 20 ml / 0,7 fl.oz / 0,1 cup cooking oil
  • 2 tbsp all-purpose flour
  • 1 l / 35 fl.oz / 4,2 cup vegetable/beef broth
  • Pepper
  • Salt

 

Recipe steps:

  1. Cut the onion into strips or rounds and fry it in butter and oil on a low flame.
  2. When the onions have softened and are not yet brown, add the flour and stir to make the flour fry nicely.
  3. Then add the broth, ideally vegetable, or beef. Add the broth cold and stirring constantly.
  4. Season with salt, pepper, bring to the boil and cook covered over a low heat for 30 minutes.
  5. Anyone who likes can add a little wine or brandy to the soup, it accentuates the taste of the soup (not adding at the end of the cooking, but about 10-15 minutes before the end to boil the alcohol).
  6. When serving, we use croutons that we have baked in the oven together with the cheese - we can even skip this step, but it would be a shame.

Ingredient choices:
  • Onions: classic yellow; a 70/30 mix of yellow and sweet onions gives a rounder flavor. Slice 3–4 mm thick so they hold texture.
  • Fat: butter plus a little oil prevents scorching and adds richness.
  • Flour (optional): 1–2 tbsp for body.
  • Stock: beef for a classic, robust profile; vegetable for a lighter, vegetarian take.
  • Wine/brandy: a dry white wine or a splash of Cognac/brandy to deglaze and balance sweetness.
  • Cheese: Gruyère, Comté, or Emmental for a good melt and nutty finish.

Technique cues:
  • Slow caramelization: medium-low heat for 30 - 45 minutes to deep gold without burning.
  • Deglaze: lift the fond with wine or a ladle of stock before adding the rest.
  • Herbs and seasoning: bay leaf and thyme; grate a hint of nutmeg if you like. Salt at the end.
  • Gratin: ladle into oven-safe crocks, top with a toasted baguette slice and cheese, and broil until bubbling.

Regional and seasonal spins:
  • Lyonnaise style: extra attention to long caramelization, finished with Gruyère.
  • Savoy twist: use Beaufort or Comté.
  • Normandy: swap part of the wine for dry apple cider.
  • Mushroom addition: sautéed mushrooms for earthiness.

Alternatives and dietary tweaks:
  • Gluten-free: skip the flour and reduce further, use GF bread for croutons.
  • Subtle smoke: a pinch of smoked paprika.
  • Acidity check: finish with a few drops of sherry or apple cider vinegar if the soup skews sweet.

Croutons and cheese:
  • Day-old baguette toasts better and absorbs without collapsing. 
  • Rub with garlic, cover with cheese, and broil to a molten cap that traps aroma.

Troubleshooting:
  • Too sweet: add acidity (wine/vinegar), a touch more salt, or black pepper.
  • Bitter notes: heat was too high; lower the flame and deglaze.
  • Too thin: simmer uncovered to reduce.
  • Too thick: loosen with stock or water.

Storage:
  • The base (without croutons and cheese) keeps 3 days refrigerated and freezes well. 
  • Adjust with stock when reheating.

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