A rich and comforting, French Onion Soup with toasty bread croutons, melted Gruyere and Swiss cheese with sweet caramelized onions cooked in a flavorful broth.
Turn the Instant Pot on Sauté(more) mode and heat butter and oil.
Add onions, salt, 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, thyme, black 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 half cup of broth and slowly stir in the soup. Set Instant Pot to Sauté mode and cook for 5 minutes as the soup thickens.
To Serve
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 ¾ cup of soup to an oven-safe bowl. Add toasted bread pieces and top them with a 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.
Video
Notes
Substitutes
Use a mix of red and yellow onions.
Dry thyme can be substituted for fresh.
StoringAny leftover soup can be refrigerated for up to 5 days or even frozen. Make sure to refrigerate or freeze the cheeses and croutons separately. Thaw the soup overnight and microwave. Then assemble the soup in ovenproof bowls and broil as per the recipe.Meal PrepThis french onion soup is perfect for meal prepping. It is a fridge and freezer-friendly recipe:
Refrigerate the pressure-cooked soup 1 to 2 days ahead. Reheat and assemble the soup bowls with croutons and cheese when ready to serve.
You can also freeze the pressure-cooked soup for up to 2 months. I would recommend freezing in individual portions so it is easy to thaw and reheat.