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French onion soup – a classic cafe dish

This classic soup is found in most French cafes known as Soupe à l’Oignon Gratinée, translated as grilled onion soup. A mainstay dish in France, which is also very popular in Belgium. The distinct smell of onions, garlic and cheese do an easy job to increase your appetite for this soup. Just like onions have many layers, so does onion soup in flavours and textures.

Key Ingredients
The rich beef stock

It is essential to have a good beef stock to make this soup shine. Homemade beef stock is traditionally used. In my blog “Why stock making is a must”, I explain the importance of stock-making for most of my dishes, mainly because it is so healthy and adds so much flavour and depth to the dish. If you prefer to use chicken stock or vegetable stock, these work fine but may lack that boldness that beef has.

TIP: Freeze portions of homemade stock for future soup making sessions.

The onions

The star of the show! Using yellow or brown onions are important as the amount of natural sugar released from these varieties are perfect for the gentle, slow frying that gives them the perfect caramelisation. This slow caramelisation, in turn, sweetens and flavours the soup enormously. If possible, try to buy organic onions for the best flavour and health benefits.

A strong cheese

The Swiss make one of the strongest and most expensive cheeses in the world: Gruyère. This cheese goes classically with onion soup for its rich flavour and excellent gooey and melting ability. Other good European cheeses to use are Emmental, Jarlsberg and Fontina mixed with a little Parmesan. Failing all the above, a strong Cheddar will do the trick. Just don’t use soft cheeses like mozzarella or feta. These will slip off the bread and drown in the soup.

The toasted gluten-free baguette

Here’s where most of us struggle to find a gluten-free onion soup in most restaurants due to the gluten baguette toast served. Homemade onion soup is possible by choosing either store-bought or homemade baguette slices. These slices are rubbed with a garlic clove, toasted slightly and finally placed on top of the soup with a generous serving of grated strong cheese.

An adobe photo of french onion soup
french onion soup cover photo

French Onion Soup

by Sandra, Fun Without Gluten
French onion soup is a classic dish from France known as Soupe à l’Oignon Gratinée.
The soup has a rich beef stock base with caramelised onions dominating, offering a sweet and salty flavour. The soup is finished off with a toasted gluten-free baguette slice and grated Emmental cheese. After the soup is briefly grilled to melt the cheese, the soup is ready to be enjoyed.
5 from 1 vote
Prep Time 30 minutes
Cook Time 1 hour 35 minutes
Total Time 2 hours 5 minutes
Servings 8



  • 5 yellow or brown onions, thinly sliced (organic, if possible)
  • 2 tbsp butter
  • 2 tbsp olive oil
  • 3 garlic cloves, finely chopped
  • 2 tsp brown sugar
  • 1 tsp fresh thyme, or
  • ½ tsp dried thyme leaves
  • 2 tbsp cornflour Known as cornflour in the UK and corn or maize starch in the USA
  • 200 ml dry white wine
  • litres store-bought or homemade beef stock


  • 1 medium store-bought or homemade gluten-free baguette bread, sliced
  • 100 g strong cheese, grated (Gruyère, Emmental, Jarlsberg)
  • 2 extra garlic cloves to rub the bread and insides of the soup bowls


  • sea salt, to season
  • freshly cracked black pepper, to season
  • 2 tsp fresh thyme leaves, to garnish (optional)



  • Melt half the butter with half of the olive oil in a large casserole stove-proof pot on medium-low heat. The butter should melt gently. Lower the heat even more if it melts too fast and sizzles.
  • Add the thinly sliced onions and allow to cook down, stirring occasionally for 20 minutes. Add the remaining butter and oil if the onions seem on the dry side.
  • Once the onions appear soft and slightly brown, add the garlic, sugar and thyme leaves and cook for a further 20 minutes until the onions appear (and smell!) caramelised. They should have a nice rich brown colour. Keep an eye on the onions and stir often to avoid burning the onions and garlic.
  • Sprinkle the cornflour over the onions and stir in well for 2 minutes, scraping the bottom of the pot to remove any residue.
  • Add the wine and enjoy the aroma as it deglazes the pan and mixes in with the onions.
  • Add the beef stock and slowly bring to the boil, then reduce the heat to a low simmer and keep it low and slow for 45 minutes with the lid on.


  • Cut the baguette bread into 5cm thick slices and rub a peeled garlic clove over both sides of the bread. Set aside on a baking tray to grill later.
  • Rub the other garlic clove on the inside of each heatproof soup bowl.
  • Preheat the grill/broiler to medium heat.
  • Briefly toast the baguette slices on both sides. Remove and set it aside.
  • Pour the onion soup evenly into each soup bowl. Place the toasted baguette slice on top of the soup and sprinkle generously with the grated strong cheese.
  • Grill the soup bowls for 10 minutes or until the cheese has melted and is slightly golden and bubbly.


  • Sprinkle the tops with some salt and the optional thyme leaves, plus some black pepper, and Voila! You have made a perfect Soupe à l’Oignon Gratinée!!


  • Keeps for 3 to 4 days in the fridge
  • Freezes well (without the baguette and cheese)
Tried this recipe?Let us know how it was!
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If you would like the onion soup to be thicker, add extra cornflour and cook with the lid off. Adding a whole peeled potato to the soup also thickens it slightly. Remove the potato before serving.


Plan ahead and make a freshly made gluten-free baguette to go with this French onion soup.


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