For me, one of the greatest joys of travelling is indulging in the rich flavours and comforting dishes each destination offers. French onion soup is a classic that always takes me back to the charming bistro in Paris, where the aroma of caramelised onions and melted cheese filled the air. It was here that I first tasted French onion soup. It’s a dish that brings warmth, flavour, and a bit of French flair to any table, and I love recreating it in my kitchen with a bit of an Irish twist. Using quality ingredients, including a crisp cider or Sauvignon Blanc, helps transform this recipe into a true taste of France.
History of French Onion Soup
The origins of French onion soup can be traced to ancient Roman times when people first combined onions, a staple food for the peasants, with broth. However, the dish as we know it today is rooted in 18th-century France.
One popular legend credits King Louis XV with creating the modern French onion soup. It’s said that one night, while at his hunting lodge, he had only onions, butter, and champagne in his pantry. Using these simple ingredients, he made a soup that became the foundation of the recipe we enjoy today.
Another story suggests that the recipe was created by King Louis XIV’s father-in-law, Stanislas Leszczyński, the Duke of Lorraine and former King of Poland. The tale goes that he arrived late at an inn and requested a meal, only to be served a bland onion soup. He then took it upon himself to add butter and bread, transforming it into a flavourful dish.
Historically, French onion soup was considered a “soup for the peasants,” as onions were cheap and readily available. It gained popularity among the working class in the Parisian markets and eventually became a beloved comfort food, often served to partygoers in the early hours of the morning.
In the 1960s, French onion soup experienced a resurgence in popularity when it became a trendy dish in French cuisine across the globe, thanks in part to the rise of French cooking in the United States. Today, it’s celebrated for its rich, hearty flavours and the delightful combination of caramelized onions, beef broth, and melted Gruyère cheese, making it a timeless and cherished classic in French culinary tradition.
Which Cheese is Used in French Onion Soup?
Gruyère cheese is the most traditional choice for French onion soup, but it’s not the only cheese that can be used. Gruyère is popular because of its nutty, slightly sweet flavour and excellent melting qualities, which create that classic, gooey topping.
However, other cheeses that are also commonly used or can be substituted include:
- Comté: Another French cheese with a similar flavour profile to Gruyère, Comté melts well and adds a rich, creamy layer.
- Emmental: This Swiss cheese is mild and melts beautifully, making it a good alternative to Gruyère.
- Mozzarella: While not traditional, mozzarella provides a stretchy, gooey texture but lacks the nuttiness of Gruyère.
- Parmesan: Sometimes added with other cheeses for extra flavour, Parmesan offers a sharp, savoury note.
- Fontina: With its buttery and slightly earthy taste, fontina melts smoothly and pairs nicely with the flavours of the soup.
You can use a combination of these cheeses or pick your favourite, but Gruyère remains the classic and most authentic choice for that signature French onion soup experience.
French Onion Soup Recipe
Here’s my version of French onion soup, perfect for cosy nights in or when you want to impress guests with an elevated starter.
French Onion Soup Ingredients:
- 700g yellow onions
- 2 cloves of garlic, crushed
- 50g salted butter
- 30ml olive oil
- 30ml balsamic vinegar
- 250ml cider (I like Stella Artois Cidre) or 250ml Sauvignon Blanc
- 1¼ litres beef stock
- 1 loaf or baguette of French bread (find my homemade bread recipe on the blog!)
- 150g grated Gruyère cheese
- Salt and pepper to season
French Onion Soup Instructions:
- Prepare the Onions: Slice the onions into thin ribbons and crush the garlic cloves. Heat the butter and olive oil in a large saucepan over medium-high heat until the butter has melted.
- Caramelize the Onions: Add the sliced onions and crushed garlic to the saucepan. Cook for about 5 minutes, stirring occasionally. Add the balsamic vinegar and continue to cook for another 5 minutes, stirring occasionally until the onions begin to brown.
- Slow Cook: Turn the heat down to low and let the onions cook gently for 30 minutes. After this time, give them a good stir, scraping up all the caramelised bits from the bottom of the pan. Cover with a lid and cook for another 30 minutes until the onions are soft and golden. Low and slow cooking is the key here.
- Add Wine and Stock: After an hour, increase the heat to medium-high and pour in the cider or Sauvignon Blanc, stirring well to deglaze the pan. Once combined, pour in the beef stock. Bring the soup to a gentle simmer, then reduce the heat to the lowest setting and let it cook for at least one hour. The longer it simmers, the richer the flavour will be.
- Season: After an hour of cooking, taste the soup and adjust the seasoning with salt and pepper as needed.
- Prepare the Croutons: Just before serving, preheat your grill or griddle pan. Slice the French bread into thick 2.5 cm slices that will fit your serving bowls. Grill the slices on both sides until they are golden. Top each slice with grated Gruyère cheese and place it back under the grill until the cheese is melted and bubbling.
To Serve:
Ladle the hot soup into bowls, place the cheesy croutons on top, and sprinkle with a little extra grated Gruyère. Serve immediately with a glass of chilled cider if you used cider in the soup or Sauvignon Blanc if you used this instead. Both options pair perfectly with the sweet, caramelised onions and nutty Gruyère cheese, enhancing every bite.
Bon appétit!
If you are hungry for more recipe blog posts, here you go.
For example, here are my recipes for casserole dish bread and gluten-free bread.
Similarly, here are my foolproof recipes for traditional Irish scones and easy flapjacks.
I also have a recipe for vegan overnight oats and baked vegan berry and banana oats.
You might also like my recipe for creamy hot chocolate.
If you want to pair wine and food, you might enjoy my guides to white wines and rosé wines.
Furthermore, if you want information on what we eat in Ireland, here is my post on the traditional Irish foods we use to celebrate St Patrick’s Day.
Finally, click here to learn about Easter in Ireland: Traditions, food, and festivities.