French Onion Soup
Prep Time 20 minutes 
Cook Time 50 minutes 
Total Time 1 hour 10 minutes 
Servings 4Ingredients
- 750 gr onion
- 75 gr unsalted butter
- 2 l vegetable stock
- 125 ml dry white wine for example a Waitrose Blueprint White Burgundy
- 1 baguette
- 200 gr Comté cheese or Gruyère or Emmental
- 1 thyme optional, for aroma
- 1 bay leaf optional, for aroma
- salt and black pepper
Equipment
Instructions
1. Prepare and caramelise the onions
- Peel and finely slice the onions. In a large saucepan over a gentle heat, melt the butter. Add the onions and a generous pinch of salt. Cook slowly, stirring often, until the onions are soft, golden, and deeply caramelised, this can take 30 to 40 minutes. Don’t rush this step is the soul of the soup.
2. Build the base
- Pour in the white wine to deglaze the onions, and allow it to bubble away, scraping up any sticky bits from the bottom of the pan. Add the stock, thyme, bay leaf, and a pinch of nutmeg. Bring to a gentle simmer, cover, and cook for 20 minutes so the flavours meld together. Season with salt and pepper to taste.
3. Prepare the bread
- While the soup simmers, preheat your grill (or oven at 200°C). Slice the baguette into thick rounds and toast them on a baking tray until golden. Generously top each slice with grated cheese and return to the grill until the cheese is bubbling and golden.
4. Finish and serve
- Remove the thyme and bay leaf from the soup. Ladle the hot soup into ovenproof bowls. Float a few cheesy croutons on top of each bowl, and if you’re feeling indulgent, scatter over a bit more cheese and pop the bowls under the grill for a few minutes until the top is gloriously gratinéed. Serve immediately, piping hot and bubbling.
Notes
- Really take your time caramelising the onions. The deeper the colour, the richer and sweeter your soup will taste. If you rush this bit, you’ll miss out on that classic, almost jammy depth that makes French onion soup so special.
- If you’re feeling a little rebellious, try a mix of Gruyère and Comté for the croutons. The blend gives you that perfect balance of melt and tang.
- Day-old baguette works best for the cheesy croutons. It holds up beautifully in the soup and soaks up all that savoury broth without falling apart.
- If you’re making this ahead, the soup itself keeps brilliantly in the fridge for up to three days. Just add the cheesy croutons fresh when you’re ready to serve.
About this recipe
When I talk about French onion soup to friends, they all make a face. I get it, it sounds strange. But please, try this recipe at least once. I promise it’s not what you think. The onions become sweet, the white wine comes through, and the cheese on top makes the whole thing unforgettable. I’m not exaggerating. Onion soup is a big deal in our house, we make it regularly in winter and we always have a smile on our faces eating it.
Where french onion soup comes from
Onion soup goes way back and has roots to Roman times, when onions were cheap, abundant, and one of the few vegetables ordinary people could get hold of all year round. For centuries it was known as the soup of the poor. Onions, bread, and whatever liquid was available. The cheese came later, once the dish made its way into kitchens with access to better ingredients.
The version most people know today became a Parisian classic in the markets of Les Halles, the great central market that fed Paris from the 12th century until it was demolished in the 1970s. Workers started their shifts before dawn and needed something hot and filling fast. French onion soup was all three. It became so associated with Les Halles that it was called soupe des Halles, and eating it in the early hours after a long night became part of Parisian life.
The legends are numerous and probably a bit embellished. Louis XV supposedly made a version with onions, butter, and champagne after a late-night hunt when he found himself hungry with nothing else to hand. The Duke of Lorraine is said to have demanded the recipe on the spot after trying it at a Champagne inn. Whether either story is true doesn’t really matter, the fascinating thing is that they exist, which tells you something about how good this onion soup is!
Why making french onion soup takes time
There’s nothing hard about this recipe, the soup itself is pretty simple to make. What you need is patience. All the flavour comes from the caramelisation of the onions, and that takes a while. Onions cooked quickly turn soft and slightly bitter. Onions cooked slowly over low heat for forty minutes to an hour turn sweet, golden, and completely different from where they started.
The temptation to turn up the heat when the onions are taking too long is understandable. But if you don’t have time, don’t make this recipe as you might get disappointed with the results. Low heat, patience, and occasional stirring. The colour should develop gradually from white to pale gold to deep amber. When the onions look almost too dark, they’re ready.
The cheese and bread topping
The cheese and bread topping is the cherry on the cake. A slice of good bread, slightly stale so it doesn’t dissolve immediately, with grated Gruyère or Comté on top adds another sweetness to this French onion soup dish. And when the whole thing goes under a hot grill until the cheese melts, bubbles, and starts to colour at the edges, it’s hard not to drool!
The bread absorbs the broth from below whilst the cheese browns from above. By the time it reaches the table, the bread has softened into the soup and the cheese has formed a crust you have to break through to get to the liquid underneath. That moment of breaking the cheese crust is the best part of eating this soup.
What to make french and onion soup in
Making french onion soup this properly requires a pot that distributes heat evenly for the long, slow caramelisation and then holds that heat steadily once the broth goes in. Cast iron is ideal for both. I use my cast iron cocotte for this recipe. The heavy base means the onions caramelise evenly without hot spots that catch and burn. The lid traps moisture during the early cooking stage, then comes off for the final caramelisation. And the interior doesn’t react with the acidity of the wine I pour in.
French onion soup after midnight
In some parts of France, particularly at weddings, French onion soup is still served after midnight as the evening winds down, a tradition that comes straight from Les Halles. But there’s another good reason to make it beyond the pleasure of eating it. Onions are genuinely good for you, especially in winter. They’re a natural anti-inflammatory, they have antibacterial and antiviral properties, and they’re particularly good for the respiratory tract when you have a cold or a cough. So if you skip the bread and the cheese and just drink the broth, you’ve basically made yourself a very French, very comforting and tasty remedy!
Share your feedback and spread the love!
If you try this recipe, I’d love to hear how it turns out! Leave a ★★★★★ rating and your thoughts in the comments, it helps fellow French foodies discover this recipe too. Snap a photo and tag @obviously.french on Instagram. Come talk about it in our Facebook group. And don’t forget to save this recipe to Pinterest so you’ll always have it handy for your next French-inspired meal!
Disclosure: Just so you know, this post contains sponsored content and/or affiliate links, If you make a purchase through these links, I may receive a small commission. Doesn’t cost you anything extra. I only link to things that are actually worth your time. All opinions are my own!
