Directions

1. Set a steamer basket in a pot. Fill with enough salted water to come just below basket; bring to a boil. Prepare a large bowl of ice water.
2. Place green beans in basket; top with garlic. Cover, and steam until green beans are crisp-tender, 4 to 6 minutes. Reserve garlic. Transfer green beans to ice water; let stand until cool. Drain; pat dry.
3. Make vinaigrette: Using the flat side of the blade of a chef's knife, mash reserved garlic into a paste. Place in a small bowl; whisk in oil, vinegar, and mustard. Season with salt and pepper. (To store, refrigerate green beans and vinaigrette separately, up to 1 day.) Toss green beans with vinaigrette, and serve.