Serves: 4 

Caroline Vital Ballestrem, founder of Aux Delices de Caroline, shares her recipe for this tasty French classic – perfect for a winter warmer!  


  • 4 large onions 
  • 2 tablespoons sunflower or olive oil 
  • 2 tablespoons butter 
  • 700 ml vegetable stock 
  • 4 slices of baguette 
  • 60g Gruyère cheese, grated 
  • Salt and freshly ground black pepper


1Peel and quarter the onions and slice or chop them into small pieces.

2Heat the oil and butter in a pan, so that the onions form a thick layer. Fry the onions briskly for a few minutes, stirring constantly. Reduce the heat and cook gently for 45 – 60 minutes. At first the onions need to be stirred only occasionally, but as they begin to colour, stir frequently. The colour of the onions gradually turns golden and then more rapidly to brown, so take care to stir constantly at this stage so that they do not burn on the bottom. When the onions are a rich mahogany brown, add the vegetable stock and a little seasoning.

3Simmer, partially covered, for 30 minutes, then season with salt and pepper.

4Preheat the grill.

5Spoon the soup into four ovenproof serving dishes and place a piece of bread in each. Sprinkle with the cheese and grill for a few minutes, until golden.

6Season with plenty of freshly ground black pepper.

About the author 

Caroline Vital Ballestrem is half-Austrian, half-German and lives with her French husband in Wimbledon, London. The daughter of gifted cooks, she started her one-woman catering company, Aux Delices de Caroline, in 2013, and then in January 2019, Caroline began writing a food blog to share her recipes. Visit  


    • Hi Maria, we are currently looking into a printer-friendly viewing option, so fingers crossed we can get that out soon! However, in the meantime to be able to print this recipe I recommend printing the whole browser. Or alternatively you could copy and paste the whole recipe into a word document and that should format the recipe better.


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