Minted Green Beans with Red Onion

• 2 pounds green beans, trimmed
• 1 teaspoon Dijon-style mustard
• 1 tablespoon white-wine vinegar
• 1/4 cup olive oil
• 3 tablespoons minced fresh mint leaves
• 1/2 cup finely chopped red onion
In a kettle of boiling water cook the beans for 2 to 4 minutes, or until they are crisp-tender, transfer them with a slotted spoon to a bowl of ice and cold water to stop the cooking, and drain them well. Pat the beans dry with paper towels and chill them, covered, for at least 3 hours or overnight.
In a large bowl whisk together the mustard, the vinegar, and salt and pepper to taste, add the oil in a stream, whisking, and whisk the dressing until it is emulsified. Add the beans, the mint, and the onion and toss the mixture until it is combined well.

From: Gourmet Magazine
http://www.epicurious.com/recipes/food/views/Minted-Green-Beans-with-Red-Onion-12549#ixzz0vVqMzJPm