Ingredients
Method
- Peel and thinly slice the onions.
- Slightly brown the butter in a frying pan at low temperature, then add the onion and sugar. Gently cook for about 30 minutes until soft.
- Pour in the vinegar and wine, then cook on medium heat for 10-15 minutes. When the onions are dark brown and the liquid is reduced to a thick sticky sauce, turn off the heat.
- Season with salt and pepper. Let it cool and transfer it into a container or immediately spoon it into sterilized jars.
- Keep the jars in the fridge or in the larder.