- 4 onions
- 1/4 tsp salt
- Pre-heat the sous-vide water to 85 degrees Celsius.
- Fry the onions over a medium heat in a dry frying pan for 15 minutes, stirring occasionally.
- Use a thick plastic bag, or double bag it, to hold the part-cooked onions and use the submersion method to get all the air out. Some plastic bags don't have strong enough edges to not break during the long and hot cooking of this recipe.
- Cook the onions for 24 hours.
- Season with the salt, divide into portions and freeze until required to flavour a recipe.