Instant Pot French Onion Soup

How the Pressure Cooker Helps

Caramelizing onions is really two jobs: softening them until they collapse and release their sugars, then browning those sugars. On the stove, both happen slowly in the same pan, and you're stirring the whole time. The pressure cooker does the first job on its own in 20 minutes. You still brown them afterward on SAUTÉ, because pressure cooking alone makes soft, sweet, pale onions without the roasted flavor.

What You'll Need

• Yellow onions. Three pounds sounds like a lot, but they cook down to about 2 cups. Sweet onions like Vidalia work but can make the soup too sweet.
• Butter. Flavor, and a head start on browning.
• Low-sodium beef broth. It's most of the soup, so buy a good one.
• Dry sherry. A nutty depth. Dry white wine or brandy work too.
• Worcestershire, thyme, and a bay leaf. They make store-bought broth taste richer.
• Baguette and Gruyère. Toasted bread soaks up the broth, and Gruyère melts into a nutty, golden top.

How to Make It

Set the Instant Pot to SAUTÉ, melt the butter, and add the sliced onions and salt. Cook 10 minutes, stirring often, until they soften and shrink by about half. Add ½ cup of broth and scrape the bottom well. Anything stuck there can trigger the BURN warning.

Lock the lid, set the valve to SEALING, and pressure cook on HIGH for 20 minutes. Let the pressure release naturally for 10 minutes, then quick release the rest.

Switch back to SAUTÉ and cook uncovered 10–15 minutes, stirring often, until the liquid is gone and the onions are deep golden brown. Stir in the sherry and scrape up the browned bits, then add the rest of the broth, the Worcestershire, thyme, bay leaf, and pepper. Simmer 5 minutes, remove the bay leaf, and taste for salt.

Heat the broiler with a rack about 6 inches from the element. Set oven-safe crocks on a baking sheet, ladle in the soup, and top each with toasted baguette and a handful of Gruyère. Broil 2–4 minutes, watching closely, until the cheese bubbles and browns in spots. Warn everyone that the crocks are very hot.

Troubleshooting

• Bland. The onions weren't browned enough, or the broth is thin. Push them to deep golden and use a good broth.
• Bitter. The onions scorched. Stir often during browning and lower the heat if they darken fast.
• Too salty. Broth, Worcestershire, and Gruyère all add salt. Taste before adding more.
• BURN warning. Something is stuck to the bottom. Release pressure, scrape the pot clean, add a splash of broth, and restart.

Variations

• Alcohol-free. Replace the sherry with extra broth plus 1 teaspoon balsamic vinegar.
• Vegetarian. Use a rich mushroom broth and a splash of soy sauce instead of beef broth and Worcestershire.
• Slow cooker onions. Cook the onions with butter and salt on LOW 10–12 hours, leaving the lid slightly ajar for the last 2 hours. Add the broth and seasonings and cook 1 hour more.
• Different cheese. Swiss, provolone, or Gruyère mixed with parmesan all melt well.
• No oven-safe bowls. Broil cheese-topped toasts on a baking sheet and float one on each bowl.

More Pressure Cooker Soups

This is the special-occasion soup. For an everyday, high-fiber bowl, Instant Pot lentil soup is on the table in about 45 minutes. Instant Pot white chicken chili and Instant Pot baked potato soup are the creamy, family-dinner options. Serve French onion soup with a crisp green salad, or next to roast chicken or steak for a bistro-style dinner.

Storing and Freezing

Cool the soup (without bread and cheese) and refrigerate it within 2 hours. It keeps 3–4 days and tastes even better the next day. Freeze it in freezer-safe containers, leaving an inch of headspace, for up to 3 months. Thaw overnight in the fridge, reheat on the stove until it's steaming hot, then add fresh toast and cheese and broil.

Cook's Tips

• Slice evenly. About ⅛ inch thick, so the onions brown at the same rate. A mandoline makes quick work of 3 pounds.
• Cut pole to pole. Halve the onions through the root and slice lengthwise. They hold their shape better in the soup.
• Toast the bread well. Dry, crisp bread holds up in the broth instead of dissolving.
• Watch the broiler. Cheese goes from bubbly to burnt in seconds.