There's nothing quite like a bowl of classic French onion soup, slow cooked onions, garlic and rich beef stock create that deep onion flavour. No need for added sugar, the onions are sweet enough on their own. A splash of white vermouth adds acidity and the bouquet garni some herbal freshness.
Serve the soup hot, and top with a toasted baguette slice, smothered in melted, herby cheese. This makes a great starter for any meal, but is also the perfect autumn lunch, or light dinner option for chilly evenings.
Despite the rich and deep flavour of this soup, it's all coming from the beef stock, white vermouth and soft, sweet onions. You get all the savoury flavour without the need for adding cream, or butter and flour thickeners.
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Why this french onion soup is worth making
- A wholesome, vegetable-forward soup that is almost entirely based on onions and garlic, which are packed with antioxidants and fibre.
- An easy to make restaurant quality dish with simple techniques and minimal prep, making it suitable for all levels of cook.
- Great for meal prep as the flavour improves if it's left to sit. You can also double the recipe making it ideal for batch cooking.
Recipe ingredients
Find the full list of ingredients and quantities in the recipe card below.
- Butter - for the best flavour I like to use butter to gently sauté the onions and garlic.
- Onions - I use brown onions in this recipe as they have a good strong onion flavour, perfect for making soup.
- Garlic - I always opt for freshly crushed garlic in this recipe as it has the best flavour. Frozen garlic is a good option too.
- Wine - I add dry white vermouth or white wine in this recipe, it adds depth of flavour and acidity which helps balance out the rich beef stock and sweet onions.
- Herbs - I like to make a bouquet garni using fresh herbs using 2 sprigs fresh thyme, 4 springs fresh parsley and a bay leaf (there's instructions how to do this later in the post). However, if you don't have fresh herbs, you can find sachets of bouquet garni in the dried herbs section of your supermarket.
- Beef stock - for the best flavour I recommend using a homemade or good quality beef stock from the supermarket, as it does provide a lot of the flavour in this soup.
- Seasoning - I keep the seasoning simple with some sea salt and freshly ground black pepper.
- Cheese croutons - the cheesy croutons to top the soup are made with thick slices of toasted French baguette. Once toasted grated Gruyere cheese and freshly chopped parsley are added to the crouton before being placed under the grill to melt the cheese.
How to make French Onion Soup
- Melt the butter in a large saucepan over a medium heat, add the onions and garlic and stir well to combine.
- Reduce the heat to low and cook the onion mixture slowly for 20-30 minutes, stirring occasionally, until the onions have softened and are caramelised. Take care not to burn the onions as this will only make the soup bitter.
- Increase the heat in the pan and pour in the white vermouth, keep stirring and reduce the wine by half.
LESLEY'S TOP TIP: Don't rush the onions, cook them low and slow so that they soften and lightly caramelise, that's what gives the best flavour.
How to prepare a bouquet garni
- While the wine is reducing, prepare the bouquet garni. Place the fresh bay leaf on a board, laying the sprigs of thyme and parsley across the centre.
- Now roll the bay leaf around the other herbs to form a tight bundle and secure with kitchen twine.
- Add the beef stock to the pan, along with the bouquet garni, salt and pepper. Bring the soup to the boil, before reducing to a low simmer. Place the lid on the pan and cook gently for 30 minutes.
- Meanwhile place 4 slices of thick cut French baguette on a tray and place under the grill. Lightly toast both sides of the bread.
- When the soup is ready check the seasoning and then ladle into some oven proof bowls. It is easier when the bowls are placed on a baking tray first as it makes them easier to handle.
- Place a piece of toasted bread on top of each bowl, sprinkle over some grated gruyere cheese and some chopped parsley. Place the tray back under the grill until the cheese has melted and is bubbling.
- Remove the soup from the oven, and cool for 5-10 minutes.
LESLEY'S TOP TIP: This soup comes straight from the oven and is piping hot. so always allow the soup to sit before serving to avoid scalding your mouth.
Recipe variations
- Onions - I used brown onions in this recipe as that's what I had at home. I like to start with brown onions as the base, but you could also add in white or red onions, or cook with a mix of all 3.
- Cheese - use a good quality melting cheese to top the toasted baguette. I opted for Gruyere, but Emmental or Comte would also work.
- Stock - use the best quality of beef stock that you can lay your hands on as it does make a difference to the flavour of the finished soup. I prefer a homemade beef stock, or a good quality fresh beef stock from the supermarket.
- Dairy free - for dairy free diners swap the butter and cheese for dairy free alternatives.
Serving suggestions
The French onion soup is a light broth based soup, however the addition of the cheesy topped croutons make it a filling bowl of soup. It makes a great autumn lunch or light dinner option. You can also serve it as a warming starter at the beginning of a larger meal.
If serving for lunch I don't tend to add anything else to the meal, however you could add some fresh salad like my Lettuce & Fresh Herb Salad. For hungrier diners, add some extra crusty bread, toast or garlic bread.
Useful hints and tips
- Take time to caramelise the onions, low and slow cooking allows the onions to develop natural sweetness without needing to add sugar. Take care not to rush this step, otherwise you risk burning the onions and making the soup bitter.
- Don't skip the garlic as it boosts the savouriness of the soup and balances out the sweet onions.
- If time allows make the soup in advance, ideally the day before, as the flavours will intensify if left to sit.
- Double the recipe and make extra to freeze as this soup recipe freezes really well.
- Use a gluten free beef stock if serving coeliacs or gluten free diners.
- Allergy advice: gluten free, egg free, soya free and nut free. For comprehensive and detailed allergy advice go to Allergy UK.
FAQs
Bouquet garni is a French term for a bundle of herbs tied together, used to flavour stocks, soups and stews. Traditionally the herbs used are bay, thyme and parsley (including both the leaves and stalks of the herbs).
Many recipes add sugar, however I find this knocks the whole taste out of balance as it's too sweet. I once got chatting to a French chef about food, and in particular French onion soup! He assured me that when cooked correctly, and for long enough, onions are sweet enough without the need to add extra sugar!
I like adding the vermouth, or wine, as it adds depth and acidity to balance out the rich beef stock and sweet onions. However, if you would rather you can leave it out.
Yes, French onion soup can be made ahead of time and reheated when you are ready to enjoy it. Once cooked allow to cool, then cover and place in the fridge for up to 2 days. However, I would recommend making the cheese crouton fresh, just before you are about to serve the soup.
Yes, French onion soup freezes really well. I usually make a double batch of the soup, so that I can enjoy some and freeze the rest for another day. Once cooked and cooled, place the soup into and airtight container freeze for up to 3 months.
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Additional recipe suggestions
If you like this recipe then try some of these great soup recipes:
- Traditional Cullen Skink
- Garlic Soup
- Courgette & Sweet Pepper Soup
- Curried Chickpea & Vegetable Soup
- Tomato Soup
- Tomato & Basil Soup
- Vegetable Barley Broth
- Spicy Bean Soup
For some great hints and tips on how to make a great bowl of soup, have a read of my 20 Simple Soup Recipes post. This features some delicious soup recipes for you to try!
French Onion Soup
Equipment
- weighing scales
- chopping board
- Kitchen knife
- kitchen twine
- large saucepan or soup pan
- serving bowls
- Baking tray
Ingredients
- 80 g butter
- 1 kg onions (sliced)
- 4 cloves garlic (crushed)
- 125 ml dry white vermouth (or dry white wine)
- 1 bouquet garni (2 sprigs fresh thyme, 4 springs fresh parsley & 1 fresh or dry bay leaf)
- 1 ltr good quality beef stock
- 1 teaspoon sea salt
- 1 teaspoon freshly ground black pepper
- 4 slices thick cut french baguette
- 120 g Gruyere cheese (grated)
- fresh parley (chopped, garnish)
Instructions
- Melt the butter in a large saucepan over a medium heat, add the onions and garlic and stir well to combine.
- Reduce the heat to low and cook the onion mixture slowly for 20-30 minutes, stirring occasionally, until the onions have softened and are caramelised. Take care not to burn the onions as this will only make the soup bitter.
- Increase the heat in the pan and pour in the white vermouth, keep stirring and reduce the wine by half.
- While the wine is reducing, prepare the bouquet garni. Place the fresh bay leaf on a board, laying the sprigs of thyme and parsley across the centre. Now roll the bay leaf around the other herbs to form a tight bundle and secure with kitchen twine.
- Add the beef stock to the pan, along with the bouquet garni, salt and pepper. Bring the soup to the boil, before reducing to a low simmer. Place the lid on the pan and cook gently for 30 minutes.
- Meanwhile place 4 slices of thick cut French baguette on a tray and place under the grill. Lightly toast both sides of the bread.
- When the soup is ready check the seasoning and then ladle into some oven proof bowls. It is easier when the bowls are placed on a baking tray first as it makes them easier to handle.
- Place a piece of toasted bread on top of each bowl, sprinkle over some grated gruyere cheese and some chopped parsley. Place the tray back under the grill until the cheese has melted and is bubbling.
- Remove the soup from the oven, take the bowls off the tray and onto a heat resistant board. Now leave the soup to sit for 5-10 minutes and allow it to cool a little before serving, to avoid scalding your mouth on piping hot soup.
Notes
• Please note that the nutrition information provided above is approximate and meant as a guideline only •
Monika Dabrowski says
I read your recipe with extra special interest as this is one soup I've always wanted to make but somehow never have. I am surprised at how uncomplicated it is! Thank you for bringing it to #CookBlogShare:)
Lesley says
Thank you Monika. I love this soup and have experimented lots over the years. A lot of recipes add sugar, but I find it overly sweet. I think the trick is taking time to let the onions soften, that makes a huge difference. I hope you enjoy. Lesley x