How to Make It
Bring a large saucepan of lightly salted water to a boil. Drop in the green beans and cook, uncovered, 5 to 7 minutes or until tender but still crisp. Drain. (Can be made ahead to this point. Rinse with cold water to stop the cooking. Place in a resealable plastic bag and refrigerate.)
Dry the saucepan and return it to the stove. Toast the mustard seeds over low heat just until they pop, about 1 minute, stirring to prevent scorching. Add the honey and vinegar and cook until the sauce boils and becomes syrupy. Add the green beans and toss.
To fake it...and save 15 minutes: Thaw three 9-ounce packages frozen whole green beans under warm running water. Place in a skillet with 1/2 cup bottled honey-mustard salad dressing. Over medium heat, toss until heated through, adding more dressing if necessary to lightly coat all the green beans. Total time: 5 minutes.