They're super easy to make and the end result is delicious.
For 2 people you need:
500g of small flat onions (you can use normal ones too, just small ones)
1 table spoon of brown sugar
1 table spoon of white vinegar
1 table spoon of balsamic vinegar
1 table spoon of olive oil
50 ml of water
a pinch of salt
Peel the onions and put them in a large heavy bottom pan with the oil. Fry for a few minutes.
In a glass mix together the water, both vinegars and sugar. Then put the mixture in the pan on top of the onions and cover with a lid. It needs to simmer for 30-40 minutes depending of the size of the onions. They need to be very soft.
Take the lid off and raise the gas under it so they can caramalize for a couple of minutes.
They're better served cold, even better the day after. If you make more you can put them in a jar and serve them with goat's cheese.