Why It Works
- The pressure cooker makes quick work of breaking down the onions for fast caramelization.
- Store-bought chicken stock is better than store-bought beef stock, with a cleaner, more natural meaty flavor that allows the onions to shine through.
- Cider vinegar, and sherry add depth and complexity to the broth.
Traditional techniques for caramelizing onions can take hours to deliver extra-sweet, complex flavor. The pressure cooker reduces that time down to about 30 minutes of hands-off cooking. Finishing off those onions with sherry, stock, and some aromatics transforms them into a soul-satisfying classic French onion soup.
This recipe was cross-tested in 2022 and lightly updated to guarantee best results. There is no longer baking soda in the recipe.
6 tablespoons unsalted butter, plus more for toasts (3 ounces; about 90g)
3 pounds yellow or mixed onions, sliced 1/8 inch thick (1.4kg; about 4 to 5 large onions) (see note)
2 teaspoons Diamond Crystal kosher salt, plus more to taste; for table salt, use half as much by volume
Freshly ground black pepper
1/4 cup (60ml) dry sherry, such as Amontillado
2 quarts (about 2L) homemade or store-bought low-sodium chicken stock
2 sprigs thyme
1 bay leaf
1 1/2 teaspoons (7ml) cider vinegar
16 bowl-size slices rustic bread, toasted until crisp
1 medium clove garlic
1 pound (450g) Gruyère cheese, grated
Freshly minced chives, for garnish
Melt butter in an electric or stovetop pressure cooker over medium heat. Without stirring, add onions. Season with salt and pepper. Seal pressure cooker and heat to high pressure (12.5 to 15 psi). Cook at high pressure for 20 minutes. Remove from heat. Let the pressure release naturally (float valve will drop; this will take about 30 minutes.) Remove lid from cooker.
Continue cooking with lid off, stirring constantly, until liquid inside has completely reduced and the onions are golden brown, about 5 minutes. Add sherry and bring to a simmer. Cook until alcohol smell is mostly gone, about 3 minutes. Add stock, thyme, and bay leaf, raise heat to medium-high, and bring to a simmer. Lower heat and simmer for 10 minutes. Add cider vinegar and season with salt and pepper to taste. Discard thyme sprigs and bay leaf.
To Serve: Preheat broiler and move oven rack to top position. Butter toasts and rub with garlic clove until fragrant. Spoon a small amount of broth into the bottoms of 8 ovenproof serving bowls, then top with half the toasts. Sprinkle some Gruyère on top of toasts, then spoon more soup and onions on top, nearly filling the bowls. Set the remaining 8 toasts in each bowl, pushing to nearly submerge them. Top with remaining Gruyère and set bowls on a rimmed baking sheet. Broil until cheese is melted and browned in spots, about 5 minutes. Garnish with chives and serve.
Add fish sauce, if using, and cider vinegar and season with salt and pepper (if necessary). Discard thyme sprigs and bay leaf.
To Serve: Preheat broiler and move oven rack to top position. Butter toasts and rub with garlic clove until fragrant. Spoon a small amount of broth into the bottoms of 4 ovenproof serving bowls, then top with half the toasts. Sprinkle some grated Gruyère on top of toasts, then spoon more soup and onions on top, nearly filling the bowls. Set the remaining 4 toasts in each bowl, pushing to nearly submerge them. Top with remaining grated cheese and set bowls on a rimmed baking sheet. Broil until cheese is melted and browned in spots. Garnish with chives and serve.
Electric or stovetop pressure cooker, rimmed baking sheet
Yellow onions are your best all-purpose bet for this soup, but a mix of yellow, sweet (e.g., Vidalia), and red onions, as well as shallots, produces an even more complex flavor.
This Recipe Appears In
|Nutrition Facts (per serving)|
|Amount per serving|
|% Daily Value*|
|Total Fat 29g||37%|
|Saturated Fat 17g||83%|
|Total Carbohydrate 41g||15%|
|Dietary Fiber 3g||12%|
|Total Sugars 11g|
|Vitamin C 10mg||52%|
|*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.|