French Onion Soup is by far the most requested soup for dinner parties with our friends and family. My vegetarian take on this rich and indulgent dish boasts flavors of caramelized onions, toasty buttered croutons, sweet thyme, and of course, melted gooey cheese.
Traditional recipes can be time-consuming; but with the help of the Instant Pot, this French onion soup is ready in under an hour. With the same luxurious flavors and sweetness from caramelized onions, topped with toasty croutons and cheese broiled to golden perfection!
Instant Pot Sauté function is perfect to cook and brown the onions. The pressure cooking option seals all the flavors inside making the onions melt-in-your-mouth creamy. Infused with bay leaf and fresh thyme, this vegetarian French onions soup is a must-try recipe.
- I like to use large yellow onions in this soup because they lend to a mellow, sweet taste with the perfect brightness in the end. You can also add a mix of onions. Make sure to thinly slice them with a mandolin,
- Traditionally made with beef broth, I love making a vegetarian version of this classic French onion soup with the Better Than Bouillon seasoned vegetable base. It increases the flavor intensity and also helps to get that perfect brown color to the soup.
- Use good quality dry white wine such as Pinot Grigio, Sauvignon Blanc, or Chardonnay. The broth along with the wine adds the perfect richness and acidity to the soup. If you are not a big wine drinker buy the smaller single-serve wine bottles.
- The Worcestershire sauce adds savory, umami flavors to the soup and is also available as a Vegan option in most grocery stores.
- Although dried thyme can be used in a pinch, I recommend using fresh thyme for more bold flavors and also adding some as a garnish while serving
- Use fresh, good-quality cheese. I like to top the soup with a handful of shredded Gruyere cheese and sliced Swiss cheese
- Finish off with a sprinkle of spicy cayenne pepper to perfectly balances the flavors of this classic bistro soup
Turn the Instant Pot on Sauté(more) mode and heat butter and oil. Add onions, ½ tsp salt, ¼ tsp sugar and cook for 20-25 minutes stirring every 5 mins until onions turn golden brown but not burnt. Glass lid can be used during Saute process. After 20 minutes the onions should be golden brown and the bottom of the pot will start to brown (Photos 1 – 4).
Press Cancel. Add wine and deglaze the pot removing all browning from the pot. Cook for 2-3 minutes as the wine evaporates. Add bay leaf, thyme, remaining salt, pepper, Worcestershire sauce, and broth. Secure the lid with Pressure Release to Sealing. Cook on Manual/Pressure Cook (Hi) for 6 minutes followed by Quick Release.
Open the Instant Pot, remove the bay leaf and discard. Mix all-purpose flour in the remaining broth and slowly stir in the soup. Set Instant Pot to Sauté mode and cook for 5 minutes as the soup thickens (Photos 5 – 8).
Next, make some homemade croutons. Slice a crusty baguette into thick bite-sized pieces. Brush them with some butter for more rich flavors and then toast them in the oven (photos 9 – 10)
Ladle the soup in oven-safe bowls. Place the bowls in a baking tray, this makes them really easy to take in and out of the oven especially when serving yo multiple people at once.
Line the toasted croutons on top of the soup. Next spread a handful of shredded Gruyere cheese and top with sliced Swiss cheese. Sprinkle spicy cayenne pepper to perfectly balances the flavors. Place the tray in the preheated oven and broiled just until the cheese melts and starts to brown. (photos 11 – 14)
Be careful when you take out the tray and serve. Enjoy hot!
Here is a quick video on how to make this crowd-pleasing, winter comfort soup in the Instant Pot:
Did you enjoy this delicious soup? Here are some more of my favorite Instant Pot Soups:
- Pasta Fagioli Soup
- Tomato Bisque
- Chicken Cilantro Soup
- Coconut Curry Noodle Soup
- Chicken Tortellini Soup
- Hearty Chicken Noodle Soup
- Chicken Tortilla Soup
- Keto Chicken Mulligatawny Soup
- EASY Lasagna Soup
- Corn Poblano Chowder
French Onion Soup Instant Pot
- 4 large yellow onions thinly sliced (use mandolin for thin slices)
- 3 tablespoons butter
- 1 tablespoon cooking oil
- 1 teaspoon kosher salt
- ¼ teaspoon sugar
- ½ cup dry white wine
- 1 tablespoon Worcestershire sauce/ Vegan Worcestershire sauce
- 1 Indian bay leaf
- 1 tablespoon fresh thyme
- ½ teaspoon crushed black pepper
- 3 cups veg broth low sodium
- 2 tablespoons all purpose flour
- 1 crusty baguette thick slices
- 1½ cups shredded gruyere cheese
- 6 to 12 slices swiss cheese
- 1 teaspoon cayenne pepper optional
- Turn the Instant Pot on Sauté(more) mode and heat butter and oil.
- Add onions, ½ tsp salt, ¼ tsp sugar and cook for 20-25 minutes stirring every 5 mins until onions turn golden brown but not burnt. Glass lid can be used during Saute process. After 20 minutes the onions should be golden brown and the bottom of the pot will start to brown.
- Press Cancel. Add wine and deglaze the pot removing all browning from the pot. Cook for 2-3 minutes as the wine evaporates.
- Add bay leaf, ½ tablespoon thyme, remaining salt, pepper, Worcestershire sauce, and 2½ cups of broth. Secure the lid with Pressure Release to Sealing. Pressure Cook (Hi) for 6 minutes followed by Quick Release.
- Open the Instant Pot, remove the bay leaf and discard. Mix all purpose flour in the remaining broth and slowly stir in the soup. Set Instant Pot to Sauté mode and cook for 5 minutes as the soup thickens.
- Preheat oven to broil(Hi). Cut each baguette slices into bite sized pieces. Line them on a baking sheet and toast until golden brown (5 to 7 minutes).
- Add 3/4 cup of soup to an oven safe bowl. Add toasted bread pieces and top them with handful go shredded Gruyere cheese, top with Swiss cheese slices and a sprinkle of cayenne pepper and thyme. Broil for 5 mins or until the cheese melts. Serve hot!