Ingredients
4 teaspoons Dijon mustard
2 teaspoons coarse-grained mustard
2 tablespoons white-wine vinegar
6 tablespoons olive oil
Coarse salt
1 1/2 pounds haricot verts, trimmed
1/2 small red onion, finely diced
Freshly ground pepper
Preparation
In a small bowl, whisk together mustards and the vinegar. Whisking constantly, add the oil in a steady stream; continue whisking until mixture is smooth and emulsified.
Prepare an ice bath; set aside. Bring a large pot of water to a boil; add salt. Add beans, and cook until crisp-tender, about 5 minutes; drain. Transfer beans to an ice bath to stop cooking; drain well.
Toss beans with onion and vinaigrette. Season with salt and pepper. Serve at room temperature.
