2 pounds green beans
1 1/2 teaspoons Dijon mustard
2 tablespoons red wine vinegar
1/4 cup plus 1 tablespoon extra-virgin olive oil
Kosher salt and freshly ground pepper
1 tablespoon chopped tarragon
1 tablespoon snipped chives
1/2 teaspoon chopped thyme leaves
1/2 pound cherry tomatoes, halved
Bring a large pot of salted water to a boil. Add the green beans and cook until they are crisp-tender, about 5 minutes. Drain and rinse the green beans under cold water until they are chilled; pat the green beans dry.
In a large bowl, whisk the mustard with the vinegar. Gradually whisk in the olive oil and season with salt and pepper. Add the green beans, tarragon, chives and thyme and toss to coat. Add the tomatoes, toss gently and serve. The salad can be refrigerated for up to 4 hours.