1) Wash the leeks in cold, running water and cut them in half along the length.
2) In a large fry pan, heat up oil. Place the whole leeks side by side. Season with salt, pepper and sugar. Cook them until the leeks turn brown.
3) Pour in wine and let it boil for couple of minutes.
4) Reduce heat and cover the pan with a lid. Cook until the leeks get tender. You may add more wine if required.