What i do with leeks is make antipasta with em. Boil the leeks until tender (if there big top and tail and cut up into about 3-4 peices) the boiling should take about 10 mins. Drain them and leave them to cool. The make a dressing out of balsamic vinegar (if you want you could syn some olive oil or depending what plan your on use a table spoon as a healthy extra b and put that in too), finely chopped garlic, and salt and pepper. Stir and cover the leeks with it and allow the dressing to soak in.