Soupe à l’Oignon Gratinée
Rich, caramelized onion soup simmered in savory beef stock, crowned with toasted baguette and melted Gruyère. Comforting, savory, and deeply flavorful with a golden, bubbly crust.
A little context
Originating in 18th-century Paris, this dish gained fame among the workers of the Halles market. Traditionally served in ceramic bowls under a broiler, it is a staple of French bistro culture, especially during cold months. Authentic versions rely on slow-caramelized onions and quality beef stock rather than shortcuts. It remains a quintessential comfort dish across France today.
Method
- 01
Prep Onions
Peel and thinly slice the onions into uniform strips.
- 02
Heat Fat
Melt butter with oil in Dutch oven over medium heat until shimmering.
- 03
Caramelize
Add onions and cook, stirring often, for 45 minutes until deep golden brown.
- 04
Add Aromatics
Stir in garlic and flour; cook 2 minutes to remove raw flour taste.
- 05
Deglaze
Pour in wine and scrape up browned bits from the bottom.
- 06
Simmer
Add stock, thyme, and bay leaf. Bring to boil, then simmer 20 minutes.
- 07
Prep Toppings
Preheat broiler. Toast bread slices until crisp on both sides.
- 08
Season
Remove thyme and bay leaf. Season soup with salt and pepper to taste.
- 09
Assemble
Ladle soup into broiler-safe bowls and float a toast slice on top.
- 10
Top Cheese
Cover toast generously with grated Gruyère, letting it pile high.
- 11
Gratinate
Broil for 3-5 minutes until cheese is bubbly and browned.
- 12
Serve
Serve immediately while hot, cautions regarding hot bowls.
Pro tips
- ✦Caramelize onions slowly for deep sweetness
- ✦Use raw Gruyère for the best melt
- ✦Toast bread separately to prevent sogginess
- ✦Watch the broiler to prevent burning cheese
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Substitutions
- beef stock → mushroom stock (for a deeper umami flavor)
- Gruyère → Comté or Emmental (similar nutty profile)
Storage
Fridge 3 days; freezes well in portioned containers up to 2 months (without bread/cheese)
What to serve with it
- Green salad with vinaigrette
- Dry red wine (Cabernet Sauvignon)
FAQ
Can I make this ahead?+
Yes. The soup base keeps well for 3 days. Add bread and cheese just before serving.
