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French onion soup

French onion soup

A deep, savoury French classic

Preparation25 Mins
Cooking Time70 Mins

Although onion soups date back to Roman times, this particular soup began life in eighteenth-century Paris as a beef broth with caramelised onions on top. Now served without the beef, the quality of the onions is crucial. You want both high acidity and high sugar levels to create a fully-flavoured soup. The best onions are Rose de Roscoff. Spanish onions, although lacking in acidity, will also work. I like to float croutons on mine, and I grate some two-year-old Comté cheese on the top. And make sure you caramelise your onions to achieve a rich, brown colour. A Frenchman's heaven!

Ingredients Required

For the soup

2 tbsp
plain flour
unsalted butter
Rose de Roscoff onions, or white onions, cut into 3mm slices
2 tsp
sea salt
2 pinches
freshly ground black pepper
dry white wine, boiled for 30 seconds
1.5 litres
cold water
1 tsp
caster sugar (optional)

For the croutons

12 x 1cm
slices baguette
Comté cheese (ideally two-year-old), grated

Cooking Method

Chef tips

"If you like a strong onion flavour, caramelise the onions for a further 15 minutes, until very dark brown. "

"By quickly boiling the wine, you are removing most of the alcohol, which has a bitterness, but keeping all the fruity qualities and acidity of the wine."

"You could replace the water with a brown chicken stock for a richer soup."


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This recipe is adapted from the book Kew on a Plate

Accompanying a very special BBC TV series, Raymond filmed with the Royal Botanic Gardens, Kew, this is the story of the nation's favourite fruit and veg. You’ll find an array of mouth-watering seasonal recipes, detailed tasting notes, and valuable tips for growing your own produce from the talented gardeners of Kew. A perfect read for the green-fingered gastronome.

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