Ingredients

• 1 cup finely chopped sweet onion
• 1 tablespoon red-wine vinegar
• 1 tablespoon grainy Dijon mustard
• 2 1/2 pounds green beans, trimmed
• 2 tablespoons extra-virgin olive oil
• 1/3 cup finely chopped flat-leaf parsley

Instructions

1. Stir together onion, vinegar, mustard, 3/4 teaspoon salt, and 1/2 teaspoon pepper in a large bowl. Marinate about 10 minutes.
2. Meanwhile, cook beans in a large pot of well-salted boiling water, uncovered, until just tender, about 6 minutes. Transfer to a large ice bath to stop cooking. Drain and pat dry.
3. Whisk oil and parsley into onion mixture, then toss with beans.
4. Artezin Mendocino Zinfandel '07 or Château de Chamirey Mercurey Rouge '07