French onion soup with caramelized onions, beef broth, melted Gruyère — the ultimate comfort soup.
French Onion Soup is the soul of French bistro cooking — slowly caramelized onions simmered in rich beef broth, topped with toasted bread and bubbling, golden Gruyère cheese. The technique is simple but the result is profound: sweet caramelized onions, deeply savory broth, and the irresistible cheese-pulled crust. It's traditionally eaten in the early hours by Parisian market workers.
Serves 4
Melt butter and oil in large heavy pot over medium-low heat. Add onions, sugar, and salt. Cook stirring occasionally for 60 minutes until deeply caramelized — golden brown. This is the most important step. Don't rush.
Add garlic, cook 1 minute.
Pour in wine and brandy, scrape any browned bits. Reduce until almost evaporated, 5 minutes.
Add beef stock, thyme, and bay leaf. Bring to simmer. Cook 30 minutes uncovered to develop flavor.
Stir in balsamic vinegar. Adjust salt and pepper. Discard bay leaf.
Toast baguette slices until golden. Rub with garlic clove if desired.
Ladle soup into oven-safe bowls. Float 2 toast slices on each. Top generously with Gruyère and Parmesan.
Place bowls on baking sheet. Broil 3-5 minutes until cheese is bubbly, golden, and slightly browned around edges.
Serve immediately while cheese is hot and stretchy. Warn diners — bowls are very hot.
Don't shortcut the caramelization — 60 minutes minimum. This is where flavor lives.
Use proper oven-safe French onion soup bowls if possible.
Use red wine for darker, deeper soup.
Add a splash of port for sweetness.
Refrigerate soup base 5 days. Toast and broil cheese fresh per serving.
French Onion Soup dates to ancient Rome, but became refined in 18th century French markets where it sustained workers through long nights.
Heat too high. Keep medium-LOW. They should sweat first, then slowly turn golden over an hour. Patience.
Per serving (500g) · 4 servings total
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