Preparation Whisk together vinegar, mustard, thyme, garlic, and 1/2 tsp each of kosher salt and pepper, then whisk in oil in a slow stream until well-blended. Cook beans in a large pot of well-salted boiling water until tender, 7 to 10 minutes. Drain, then toss with dressing and season with salt and pepper. Serve warm or at room temperature.
Preparation Whisk together vinegar, mustard, thyme, garlic, and 1/2 tsp each of kosher salt and pepper, then whisk in oil in a slow stream until well-blended. Cook beans in a large pot of well-salted boiling water until tender, 7 to 10 minutes. Drain, then toss with dressing and season with salt and pepper. Serve warm or at room temperature.