Onion soup is sweet and simple.

Onion Soup

French onion soup is a silky brown liquid, sweet and savoury, towards the bland side of the taste spectrum. It can be spiced up with (bits of chilli and) cheesy crostini but I like it as it is. Traditionally, it’s finished in the oven with a piece of bread plonked on the surface of the soup and covered in grated cheese. It’s delicious with or without cheesy bread.

Prep: 20 minutes. Cooking time: up to 1 hour.
Stores: In the fridge, 3-4 days. In the freezer, up to 3 months.


  • Chopping board
  • Knife
  • Large pot (stock pot, pasta pot, a soup pot even)
  • Measuring jug
  • Tablespoon or tablespoon measures


  • 2 tablespoons oil
  • 1 kilo of onions, finely sliced
  • 4-6 cloves garlic, finely chopped
  • Pinch of bicarbonate of soda
  • 1 table spoon plain flour
  • 1/2 litre vegetable stock
  • 1 tablespoon soy sauce
  • 1 half red chilli, finely chopped (optional)
  • Salt and pepper to taste


  1. Heat the oil in the pan.
  2. Slice the onions finely (2-3mm slices) and add to the pot. (Add them as you go or the work surface will overflow with onion.) Stir. Keep the heat medium so you don’t burn them.
  3. Crush or finely chop the garlic and add it to the pot. Continue stirring.
  4. If you’re daring, add a pinch of bicarbonate of soda. It lowers the pH of the onions and helps promote browning reactions. For the best soup, you want to brown the onions, caramelise them into a deep golden-brown flavour. This gives the soup a fab colour but, much more importantly, it’s what makes the flavour sweet and deep. Caramelising the onions might take up to half an hour, but it’s worth it! The bicarb is supposed to speed up the process.
  5. Meanwhile, boil the water and make up half a litre of stock in the measuring jug.
  6. When you’re happy with the colour and texture of the onions, add the flour and stir that in. It will mix with the oil and moisture from the onions and create a paste.
  7. Start adding the stock, a quarter of a litre to start with, stirring constantly. Stirring is important here or the flour mixture might go lumpy when it reacts with the stock.
  8. Add the rest of the stock.
  9. Add soy sauce for flavour and a deeper colour.
  10. Let simmer for up to 45 minutes. The end product should be silky smooth, fragrant and golden brown.

Serve with cheese crostini, if you want to, or with a hunk of bread.


  • Add a third of the water and a couple of tablespoons of sugar, call it onion jam. Brilliant with blue cheese, or on toast.
  • Use white onions instead of yellow ones – they make a really sweet soup.
  • Whiz with a stick blender, and serve with a tablespoon of créme fraiche for a sophisticated take.

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