A medieval French peasant soup that became Parisian café fare in the 18th century. Les Halles, the city's central market until 1971, made it famous as a 4 a.m. dish for porters and butchers ending overnight shifts — the cheese-toast-on-broth format you now eat at brasseries was perfected there. Despite the name attached to Alsace in some menus, the gratinéed Parisian style is the canonical one.
Paris Les Halles all-night onion soup, fed to porters and theater-goers since the 1700s — onions caramelized for 45 minutes, beef stock, baguette toast, gruyère broiled to a crust. The crust is what makes it gratinée.
A heavy crock with mahogany broth, a raft of toasted bread on top, and a bubbled, browned crust of Gruyère welded over the rim. Spoon through the cheese to find onions cooked into near-jam beneath. Broth is dark from caramelized onion sugars, not from gravy browner. Burns the roof of your mouth if you don't wait.
The onions need 45 minutes to an hour of slow cooking — not 15. The dark broth comes from Maillard browning of onion sugars on the pan bottom, scraped up repeatedly with a splash of liquid (deglazing). Rush the onions and you get sweet, pale soup that tastes raw. Beef broth is traditional but a good chicken or vegetable stock works; what doesn't work is starting with bouillon cubes — there's nowhere for the deception to hide.
Variations
Lyon version adds a splash of port and an egg yolk under the toast; Provençal cooks substitute chicken stock and add a pastis splash; some Norman versions use cider instead of wine; the bistro 'à la pistou' tweak adds basil-garlic puree.
On the Palate
Where Soupe à l'Oignon Gratinée sits in the French flavor cloud
Everything rides on caramelizing the onions slowly — 30 to 45 minutes over medium heat until deep amber, because that Maillard browning is the only source of the soup's dark, sweet depth.
Ingredients
How it's made
4 steps · 1 hour
- 130 min
Peel and thinly slice the onions. Melt butter in a large pot over medium heat until it foams. Add the onions and cook, stirring often, until they turn a deep golden brown and caramelized, about 30 minutes. The onions should be very soft and sweet-smelling.
Watch outWatch the color, not the clock alone — pull them when they're a deep even golden-brown, soft, and smelling sweet.
- 25 min
Pour in the white wine and scrape up any brown bits from the bottom of the pot. Let it simmer until the wine reduces by half, intensifying the aroma.
Watch outAfter the wine goes in, scrape every brown bit off the pan bottom; that stuck-on layer is where the flavor lives.
- 320 min
Add the beef stock to the pot, along with fresh thyme. Bring the soup to a gentle simmer, allowing the flavors to meld together and the broth to reduce slightly.
- 45 min
Preheat your broiler. Ladle the soup into oven-safe bowls. Top each with a slice of bread and a generous amount of cheese. Place under the broiler until the cheese is bubbly and golden brown.
Watch outUnder the broiler, pull it the moment the cheese is bubbling and spotted golden-brown, before it burns.
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