Sous Vide Caramelised Onions
Prep time
Cook time
Total time
If you've got a sous vide machine, you can make caramelized onions ahead and tasty French Onion Soup is only 30 minutes away.
Recipe type: Soup
Cuisine: French
Serves: 2
  • 1 kilogram (2 pounds) brown onions, sliced thinly.
  • 1 clove garlic, crushed
  • ¼ teaspoon salt
  • 2 tablespoons butter
  • 1 tablespoon cooking oil
  • 4 small sprigs of fresh thyme
  • 3 stalks of fresh parsley
  • 1 bay leaf
  • salt and pepper to taste
  • 1 baguette cut into four one-inch slices.
  • 250
  1. Heat a skillet to medium heat and add the butter and oil. When the butter melts add the onions and sprinkle with salt. Don't brown the onions, you only want them to go translucent. When that begins to happen, add the garlic and cook for a minute or so but don't let the garlic brown.
  2. Remove from heat and cool completely.
  3. Preheat sous vide machine to 85C / 186F
  4. Vacuum seal the cooled onions and place in the sous vide machine and leave them there for up to 24 hours. The length of time determines how long you leave them in the water bath. Mine stayed 24 hours and came out a rich dark color.
  5. When the onions are done you can remove and place in the refrigerator for up to 3 days (perfect for dinner party preparations)
  6. If you're going to make the soup right away, add the onions to a large stock pot on medium heat and bring to the boil. The onions will have some juice in the cooking bag.
  7. Add one ladle of stock and cook for a few minutes to reduce and add another ladle of stock and repeat one more time until you've reduced 3 ladles of stock.
  8. Add the remainder of the stock and the herbs tied with some cooking twine. Cook for 30 minutes and then taste for seasoning.
  9. I can't tell you how much salt to use because stock varies and some is very salty so if I said use a teaspoon of salt it could be like the Dead Sea. Taste the soup. If it needs salt, add some. I used ½ teaspoon of salt and ¼ teaspoon of pepper.
  10. Place sliced baguette on a grill pan or under the griller/broiler to toast.
  11. Add soup and top with two slices of baguette and cover with shredded gruyere.
  12. Place bowls in the oven under the griller/broiler until the cheese is melted and bubbly. Be careful as bubbly can turn to burnt in under a minute. Best to watch.
  13. Serve immediately but the soup will be very hot.
Most of the time is hands-off but it does take about 24 hours in the sous vide machine for well caramelized onions.
Recipe by Orgasmic Chef at