Elegant, from The Art of Simple Food.
6 medium leeks (about 3 lbs)
2 tsp Dijon mustard
1 tbsp red wine vinegar
1/4 cup olive oil
2 tbsp parsley, chopped
Trim away the tough dark green tops and outer layers. Trim the roots while still allowing the leeks to hold together at the bottom. Wash repeatedly under cold water to remove all the grit between the leaves.
Bring a large pot of water to a boil and add the leeks whole. Cover and cook until the thickest part of the leeks are tender when pierced with a knife, about 7-12 minutes depending on the thickness of the leeks.
When the leeks are tender, carefully remove them to a bowl of ice water and allow to cool. Then drain them and gently squeeze out any excess water. Cut the leeks lengthwise into halves or quarters and place them on a platter.
Mix the red wine vinegar, Dijon mustard and some salt and pepper. Whisk in 1/4 cup of olive oil until the vinaigrette emulsifies. Pour over the leeks and garnish with some chopped parsley.