Classic French Onion Soup with Gruyère Toasts

Granny Birch came in through the back door with rain on her shawl and a basket of onions on her arm. “Onion soup,” she said. “The kind your grandfather made on the first cold weekend of the year.” Gerzsi tied his neckerchief a little tighter and got out the big pot.

Truffle was already up on the vegetable shelf, sorting the onions by size. He peeled every one and stacked the skins in a tidy pile. Then Gerzsi started slicing, and the tears started too. Gerzsi cried. Truffle cried. Granny Birch put on her reading glasses, which did not help at all.

Eight cups of onions went into the pot with a little oil and butter. After ten minutes they were soft. After twenty they were only just golden. Gerzsi reached for the knob to turn up the heat. Chef Tamás was walking past with a crate of bread. He set it down, turned the knob back to medium-low and tapped the recipe card where it said 30 to 40 minutes. Then he picked up his crate and kept walking.

So Gerzsi stirred. Granny Birch told him about the winter the river froze, which took almost exactly 35 minutes. By the end of the story the onions were deep brown and sweet, and the whole inn smelled like a Sunday.

Clyde pushed his head through the window just as the cheese went under the broiler. “Is this soup for horses?” he asked. “It’s for everybody,” said Granny Birch. Clyde got the end of the baguette, dipped in broth. He said it was nearly as good as an apple.

Why this one works

Low heat and plenty of time let the natural sugar in the onions brown slowly without burning, and that browning is where the flavor of the soup comes from. A splash of port or sherry loosens the brown bits stuck to the pot. The bread is toasted before it goes on the soup, so it soaks up broth without turning to mush under the cheese.

Classic French Onion Soup with Gruyère Toasts

• Servings: 12 small bowls (about 2 1/4 quarts / 2.1 L)
• Prep Time: 20 minutes
• Cook Time: 2 hours
• Time: 2 hours 20 minutes
• Difficulty: Easy
• Print

Slow-browned onions simmered in beef broth with a splash of port, topped with garlic toasts and melted Gruyère.

Ingredients

For the soup:
• 2 tablespoons (30 ml) olive oil
• 1 tablespoon (14 g) butter
• 8 cups thinly sliced onions (about 3 lb / 1.4 kg)
• 3 garlic cloves, minced
• 1/2 cup (120 ml) port wine or dry sherry
• 2 cartons (32 oz / 946 ml each) beef broth
• 1/2 teaspoon pepper
• 1/4 teaspoon salt
For the toasts:
• 24 slices French baguette, 1/2 inch (1.3 cm) thick
• 3 tablespoons (45 ml) olive oil
• 2 large garlic cloves, peeled and cut in half
• 3/4 cup (about 75 g) shredded Gruyère or Swiss cheese

Directions

1. Warm the 2 tablespoons of oil and the butter in a Dutch oven over medium heat. Add all the onions and stir now and then until they wilt and turn soft, 10 to 13 minutes.
2. Turn the heat down to medium-low. Keep cooking and stirring every few minutes, scraping the bottom of the pot each time, until the onions are a deep golden brown. This takes 30 to 40 minutes. If they start to stick, add a spoonful of water. Add the minced garlic for the last 2 minutes.
3. Pour in the port or sherry and scrape up the brown layer on the bottom. Let it bubble until about half of it has cooked away.
4. Add the broth, pepper and salt. Bring the soup to a boil, then lower the heat, cover and simmer for 1 hour, stirring once in a while. Boxed broth is often salty, so taste before you add any more salt.
5. While the soup simmers, heat the oven to 400°F (200°C). Brush both sides of the bread with the 3 tablespoons of oil and lay the slices on a rimmed baking sheet. Bake until crisp, 3 to 5 minutes per side. Rub one side of each toast with the cut side of a garlic clove.
6. Set broiler-safe bowls or ramekins on a baking sheet and ladle in the soup. Float 2 toasts in each bowl and scatter the cheese over the top. Broil about 4 inches (10 cm) from the heat until the cheese melts and bubbles, 1 to 2 minutes. The bowls will be very hot, so serve them on plates.

A sharp knife or a mandoline makes thin, even onion slices, and even slices brown at the same speed. No broiler-safe bowls? Melt the cheese on the toasts on the baking sheet under the broiler, then set them on top of the soup in ordinary bowls. The soup itself (without the toasts and cheese) can be made a day ahead. Cool it, keep it covered in the fridge and reheat it on the stove. These are small starter portions. For a main course, serve 6 bigger bowls with 4 toasts each.

🛒 Worth buying for this recipe

• Le Creuset 5.5 qt Round Dutch Oven. The 5 to 6 quart winner in America’s Test Kitchen’s Dutch oven test. A heavy enameled pot browns onions evenly and does not scorch easily over a long, low cook. Check price. See it on Amazon
• Cuisinart Chef’s Classic 7 qt enameled cast iron casserole. The Best Buy in the same America’s Test Kitchen test. Big enough for 3 pounds of onions and 2 quarts of broth. Check price. See it on Amazon
• Victorinox Fibrox Pro 8″ Chef’s Knife. The winner of America’s Test Kitchen’s chef’s knife test. Sharp and light, so slicing 3 pounds of onions goes faster. About $47 at the time of their review. See it on Amazon
• Super Benriner Mandoline Slicer. America’s Test Kitchen’s best overall mandoline. It cuts every onion slice the same thickness. Use the hand guard. About $39 at the time of their review. See it on Amazon
• Cuisinart Box Grater. The best box-style grater in America’s Test Kitchen’s grater test. Quick work for the Gruyère. About $19 at the time of their review. See it on Amazon
• Nordic Ware Baker’s Half Sheet. The winner of America’s Test Kitchen’s rimmed baking sheet test. It toasts the baguette slices and carries the bowls under the broiler. Check price. See it on Amazon
• Rösle Hook Ladle with Pouring Rim. America’s Test Kitchen’s best overall ladle. The pouring rim keeps drips off the edge of the bowl. About $54 at the time of their review. See it on Amazon
• FAAY 13.5″ Teak Cooking Spoon. A co-winner in America’s Test Kitchen’s wooden spoon test. Its flat edge scrapes the brown layer off the bottom of the pot. Check price. See it on Amazon

How Chef Tamás makes it

Chef Tamás makes this soup with his own beef stock instead of store-bought broth, and he adds leeks or red onions to the yellow ones. He caramelizes the onions using only their own sugar, and stirs in butter at the end to make the soup silky. For the top he sometimes uses Emmental, Parmesan or a smoked cheese instead of Gruyère.

At his restaurant it goes on the daily menu, mostly in autumn and winter.

Tools we use

Tamás says you can make it in any pot, as long as you keep an eye on it so the onions don’t catch on the bottom. What he reaches for:

• A cast-iron pot or Dutch oven. See the ATK pick on Amazon
• A mandoline for the onions, or a knife and some patience. Mandoline: See the ATK pick on Amazon. Knife: See the ATK pick on Amazon.
• Broiler-safe soup bowls or cocottes for the cheese.

Tamás didn’t name brands for this one. The linked models are the testers’ picks for the same jobs.

Chef Tamás’s tricks

• The trick is patience. Wait until the onions reach the right deep color.
• A pinch of salt at the start helps the onions release their juices.
• Finish the soup with a little butter for a silky texture.
• The mistakes he sees most: the heat is too high and the onions burn, store-bought broth makes it too salty, the cheese doesn’t melt nicely or it burns, and there are too few onions.
• If the cheese turns lumpy, an immersion blender and a strainer will make the soup smooth again, if you like it that way.
• His Hungarian twist: a pinch of sweet or hot paprika. He also serves it with a paprika foam and crisp bread shavings, or in a toasted seeded bun.

Adapted from French Onion Soup on Taste of Home. Cooked our way at the inn.

Sources

• Taste of Home: French Onion Soup
• America’s Test Kitchen: The best Dutch ovens
• America’s Test Kitchen: The best chef’s knives
• America’s Test Kitchen: The best mandolines
• America’s Test Kitchen: The best graters
• America’s Test Kitchen: The best rimmed baking sheets
• America’s Test Kitchen: The best ladles
• America’s Test Kitchen: The best wooden spoons
• Good Housekeeping: 2023 Bedding Awards