Keto Instant Pot Beef and Onion Soup
⏲ ~35 min total · prep 15 · cook 20 · 4 servings
Dinner⏱ 60 min total🔥 4.3g net carbs
By the KFI Test Kitchen · Tested & approved by Jason Lieu, KFI recipe editor
Published Sep 15, 2026 · Updated Sep 15, 2026
Ingredients
- 1 1/2 lb beef chuck, cut into 3/4-inch cubes
- 3 large yellow onions, halved and sliced thin (about 6 cups)
- 3 tbsp butter
- 1 tsp salt, divided
- 1/2 tsp black pepper
- 1/2 tsp dried thyme
- 1 tbsp Worcestershire sauce
- 6 cups beef broth
- 1 bay leaf
- 1/2 cup shredded Gruyère
Instructions
- Melt the butter in the Instant Pot on Sauté (More) and add the onions with 1/2 teaspoon of the salt; cook 12-15 minutes, stirring every 2-3 minutes, until deep amber and jammy — the color is the flavor, so take them past golden but pull them before they blacken.
- Push the onions to the side and brown the beef cubes 3-4 minutes on two sides, working in batches if the cubes start steaming instead of searing.
- Stir in the Worcestershire, thyme, pepper, and bay leaf, pour the broth down the side, and scrape the bottom completely clean so the pot doesn't read "burn."
- Lock the lid, set the valve to Sealing, and pressure cook on HIGH for 13 minutes.
- Let the pressure release naturally for 10 minutes, then quick-release whatever remains.
- Fish out the bay leaf, taste, and adjust the salt — the reduction varies by pot.
- Ladle into 4 bowls and melt the Gruyère over each: 2 minutes under the broiler in oven-safe bowls, or simply rest the cheese-topped bowls for a minute until it slumps and turns glossy.
Why this recipe works
- Deep amber onions in one pot Twelve to fifteen minutes on Sauté (More) builds the amber, jammy base french onion soup is known for. The color is the flavor, so this step earns its quarter hour.
- Thirteen minutes under pressure Chuck cubes that need hours on a stove turn spoon-tender in 13 minutes at HIGH pressure. The onions keep their sweetness because the pot does the rest without boiling them pale.
- Gruyère without the crouton The cheese melts straight onto the soup, under the broiler in oven-safe bowls or rested on top until it slumps and turns glossy. All of the finish, none of the bread.
Tips for making this recipe well
Take the onions past golden
Stir every two or three minutes and aim for deep amber, not black. Golden onions make a pale soup; blackened ones make a bitter one.
Brown the beef in batches
Crowded cubes steam gray instead of searing brown. Two sides, three or four minutes, and out until every cube has had its turn.
Scrape the pot completely
Pour the broth down the side and sweep the bottom clean before locking the lid. Any fond left stuck reads as burn and shuts the cook cycle down.
Let the pressure fall on its own
Ten minutes of natural release keeps the broth calm and the beef intact. Quick-release whatever remains, standing back from the valve.
Taste before you salt
Half the salt went in with the onions, and reduction varies by pot, so ladle, taste, then season. The rest is a starting line, not a finish.
Serving suggestions
Ladle into four warm bowls and melt the Gruyère over each; two minutes under the broiler if the bowls are oven-safe, or a minute of waiting while it slumps and turns glossy on its own. At 4.3g net carbs a serving, this is french onion soup with the bread retired. A sharp green salad next to it is all the meal needs. Eat it while the cheese still stretches.
Storage and meal prep
The soup base keeps 3 to 4 days refrigerated and tastes deeper on day two. Freeze it for 2 to 3 months without the cheese; thaw overnight in the fridge and reheat to a simmer on the stove. Melt Gruyère onto each bowl fresh at serving, never before storing, or the top turns rubbery in the fridge. The onions soften further each day, which is no complaint from us.
Variations worth trying
- Provolone or Swiss Both melt cleanly over the bowls if Gruyère is out of reach. The flavor leans milder; a pinch of thyme covers the distance.
- Mushroom version Slice a batch of creminis in with the onions. They amber along with them and deepen the broth.
- Double beef Two pounds of chuck in the same broth and the same 13 minutes at pressure. The pot handles it, and the soup gets heartier.
Frequently asked questions
Why did my Instant Pot say burn?
Fond was still stuck to the bottom when the lid locked. After browning, pour the broth down the side and scrape until the bottom is completely clean.
Can I caramelize the onions for less time?
You can stop at golden, but the soup will taste of it. Deep amber is where french onion flavor comes from, so give the onions their twelve to fifteen minutes.
Can I make this on the stove?
Yes. Brown and caramelize in a heavy pot, add the broth, and simmer until the chuck is tender; the stove decides the time, so test a cube.
Do I need the Worcestershire sauce?
It rounds out the broth with a depth the onions alone don't reach. Leave it out if you must; the soup still works, it sings quieter.
My onions blackened. Is it ruined?
Bitter, not ruined. Scrape out the blackened pieces with the fond you can't save, add a splash of broth to loosen the rest, and start the amber stage again with fresh butter.
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