Trim the ends off the leeks and peel off the tougher outer layer. Rinse and drain.
Heat a few tablespoons of olive oil in a pan and gently fry the leeks over a low heat for about 15 minutes, turning regularly until soft. Add a good splash of balsamic vinegar to the pan and allow it to thicken and coat the leeks. Remove from the heat and sprinkle on some Maldon salt and freshly ground black pepper.
The leeks could also be roasted and then balsamic added at the end.
This is a great side dish, part of a meze platter, a picnic, or add to a salad.