French Onion Soup Recipe

This French Onion Soup recipe transforms slowly caramelized yellow onions into a rich, comforting Parisian bistro classic finished with crisp baguette and a generous layer of melted Gruyère cheese. Featured on Dinner in Paris with host Romain Avril, this magnificent soup builds deep flavour with butter, thyme, garlic, dry white wine, Brandy, and beef stock before being broiled until the cheese becomes bubbling and beautifully golden.

The Inspiration

French Onion Soup is one of the most recognizable dishes associated with traditional Parisian bistro cooking. Its ingredients are straightforward, but the finished soup develops remarkable depth through slow cooking, careful reduction, and a final layer of toasted bread and melted cheese. Instead of relying on a long list of seasonings, the recipe allows onions to become the foundation of nearly every spoonful.

On Dinner in Paris, host Romain Avril prepares this classic by giving the onions enough time to caramelize properly. One kilogram of thinly sliced yellow onions is cooked slowly in butter and olive oil with salt for approximately 50 to 60 minutes. During that time, the onions move through several stages, beginning crisp and pale before softening and eventually developing the deep amber colour that gives French Onion Soup much of its characteristic flavour.

The result is comforting yet refined, rustic yet elegant. This French Onion Soup demonstrates how patient cooking and familiar ingredients can create a dish with deep flavour and unmistakable French character.

Ingredients

1 kg (2.2 lb) yellow onions, thinly sliced
¼ cup unsalted butter
2 tbsp olive oil
1 tbsp salt (plus more to taste)
1 tsp black pepper (plus more to taste)
3 garlic cloves, minced
4 sprigs of thyme, leaves picked
120 ml (½ cup) dry white wine
¼ cup of Brandy
5 L (6 cups) beef stock
1 baguette, sliced into 1.5 cm (½ inch) rounds
150 g (1½ cups) Gruyère cheese, grated
¼ cup fresh chives, chopped

Method

Heat butter and oil in a large heavy pot over medium-low heat.
Add onions and salt. Cook slowly for 50–60 minutes, stirring every 5 minutes.
Do not allow onions to burn, lower heat if necessary.
Onions will go from crisp white to soft and amber colour.
Add garlic, thyme leaves and pepper and cook for the last 5 minutes.
Add wine and Brandy and scrape the bottom of the pot.
Adjust the temperature to medium. Simmer for 5 minutes until reduced slightly.
Add beef stock and bring to a gentle simmer. Simmer uncovered for 20–25 minutes.
Meanwhile, prepare the bread. Pre-heat oven to 375F.
Arrange baguette coins on a baking tray. Drizzle olive oil over the top and season with salt and pepper.
Toast baguette slices in the oven for 6-8 minutes until crisp.
Remove from the oven and reserve for the last touches on the soup.
Taste the soup to ensure the seasoning is right. Ladle soup into ovenproof bowls.
Adjust the setting of the oven to a high heat Broil.
Add toasted bread on the soup and top generously with cheese.
Place under broiler for 2–4 minutes. Remove from the oven once the cheese is nice and golden brown.
Let the soup rest 2-3 minutes and top with chives. Enjoy!

Serving Suggestions

French Onion Soup is an ideal choice for a comforting lunch, cozy dinner, French-inspired gathering, or elegant first course. The combination of deeply caramelized onions, rich beef broth, crisp baguette, and melted Gruyère makes each individual bowl substantial enough to feel satisfying on its own, while the dramatic golden cheese topping gives the dish a polished restaurant-style presentation.

For a classic bistro-inspired meal, serve the soup directly in the ovenproof bowls used for broiling. The toasted baguette should remain visible beneath the bubbling Gruyère, allowing diners to break through the cheese and bread with a spoon before reaching the onion-rich broth underneath. Because the bowls emerge extremely hot from the broiler, they should be handled and served carefully.

For a colder-weather dinner, serve larger portions as the main course and allow the soup’s rich broth and melted cheese to take centre stage. The fresh chives provide a clean finishing note and a subtle pop of green against the deeply browned cheese.

Final Thoughts

This French Onion Soup recipe demonstrates why slow cooking can be just as important as the ingredients themselves. The recipe begins with familiar yellow onions, but allowing them to cook gradually for 50 to 60 minutes transforms their colour, texture, and flavour.

Find more recipes from Dinner in Paris here!