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Red Onion and Balsamic Vinegar Soup

Prep 10 minutesCooking 2 hours 30 minutes4 people

French onion soup is a true classic and rightly so. Here, the recipe is adjusted so that it can be enjoyed by vegans, with the 1.17 Balsamic Vinegar of Modena adding sweetness and sharpness while also adding the depth of flavour that would traditionally come from a meat-based stock. Replacing the molten cheesy crouton is a hearty slice of toast covered with creamy vegan crème fraiche and a thick layer of our tangy, peppery Grape Must Mustard. A note on the onions – they really cannot be hurried and do need around two hours to become incredibly soft, so the recipe does need time, but aside from this, is very simple.


2 hours 30 minutes

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6 small / medium red onions

125ml Cornicabra Extra Virgin Olive Oil

2 tsp salt

1 tsp plain flour

1 sprig chopped fresh thyme

3 tbsp 1.17 Balsamic Vinegar of Modena

600 ml vegetable stock

1 tbsp light soy sauce

4 pieces of sourdough / rustic style bread

150g vegan crème fraiche

8 tsp Grape Must Mustard


  1. Peel and slice the onions as finely as possible (a mandolin is ideal for this job). Place a large pan on a medium heat, when hot add the olive oil followed by the onions and salt. Stir so that the onions are coated with the salt and oil. The onions need a long, slow cook so keep the heat on medium till they soften and begin to sweeten and then turn down to low. You do not want any dark caramelised pieces as they will taste bitter, so if you see them darkening turn the heat down straight away. Keep stirring from time to time to ensure that they are not sticking. They will taste good after one hour, but they really do need 2 hours, or even more if you have the time, to ensure that they are completely soft. Always keep the heat on low and keep stirring and eventually they will get there.
  2. When the onions are very soft and sweet, bring the vegetable stock up to a simmer.
  3. Add the thyme to the onions and cook for a few minutes, then add the Balsamic Vinegar. Turn the heat up and keep stirring so that it evaporates and aids the caramelisation of the onions.
  4. Add the flour to the onions and cook for around two minutes, still on low to medium heat, stirring to scrape off anything that sticks to the bottom. Now add about half of the stock and keep stirring to break down any lumps of flour, then add the remaining stock and soy sauce. Turn the heat up so that the soup comes to a boil then turn down to a simmer and cook for 10 minutes.
  5. Taste the soup and add more salt if necessary – it will probably need a pinch because of the variation in strength of stock cubes but taste first then decide.
  6. When ready to serve, warm 4 bowls in an oven at 60C then toast the bread till lightly brown. Spread a decent spoonful of the oat crème fraiche all over each piece then spread 2tsp of the mustard on top of each piece. Divide the soup between bowls then one of the croutons on top and allow to soak into the soup for a minute before serving.

Included in this Recipe

Cornicabra Extra Virgin Olive Oil 500ml

Cornicabra Extra Virgin Olive Oil 500ml

Spanish single varietal extra virgin olive oil made from olives grown in Andalucia, this oil is perfect for cooking and for making dressings.

1.17 Balsamic Vinegar of Modena

1.17 Balsamic Vinegar of Modena

Our lowest density balsamic is 17% thicker than water, with a good acidic punch