2 pounds small potatoes, cut into bite-sized chunks
4 tablespoons dry white wine
6 tablespoons champagne vinegar
8 ounces slender green beans, trimmed
1 tablespoon grainy Dijon mustard
2 teaspoons salt
1 teaspoon freshly ground black pepper
3/4 cup extra-virgin olive oil
1 cup halved cherry tomatoes
1 bunch scallions, trimmed and thinly sliced (about 1/4 cup)
1/2 cup finely chopped flat-leaf parsley
1/4 cup chopped fresh basil leaves

1. Cook the potatoes in a large pot of heavily salted water until they are just done. Drain the potatoes and return them to the hot pot to let any remaining moisture evaporate away. While the potatoes are still warm, place them in a large bowl and toss them with the wine and vinegar. Let the mixture sit for a few minutes to let the potatoes absorb the liquid.
2. Cook the greens beans in a large pot of salted water until tender, about 10 minutes. Immediately transfer them to a bowl of ice water to stop the cooking and set the color. Drain well and set aside.
3. Whisk together the mustard, salt, pepper and olive oil in a small bowl.
4. Pour the olive oil mixture over the potatoes and stir gently until the potatoes are coated.
5. Gently stir in the beans, tomatoes, scallions, parsley and basil.
6. Season to taste with additional salt and pepper.
7. Serve warm or at room temperature.

Makes 6 to 8 servings.