Ingredients

1 1/2 pounds white new potatoes, scrubbed

Coarse salt and ground pepper

1/4 cup white-wine vinegar

1 tablespoon Dijon mustard

1 tablespoon whole-grain mustard

3 tablespoons olive oil

1 stalk celery, thinly sliced crosswise

1/2 cup celery leaves

Preparation

Place potatoes in a medium saucepan, and cover with cold salted water. Bring to a boil, reduce to a simmer and cook, until just tender, 12 to 14 minutes. Drain; set aside to cool slightly.

Meanwhile, in a medium bowl, combine vinegar, Dijon, and whole-grain mustard; season with salt and pepper.

When potatoes are cool enough to handle, quarter them, and toss with mustard-vinegar mixture. Refrigerate until completely cold, about 2 hours. Add oil, celery, and celery leaves to potatoes; toss and serve.