Ingredients
1 1/2 pounds Yukon gold potatoes, scrubbed and cut into 3/4-inch cubes
2 tablespoons olive oil
1 tablespoon Dijon mustard
1 tablespoon white-wine vinegar
4 celery stalks, halved lengthwise and thinly sliced
2 scallions, thinly sliced
Coarse salt and ground pepper
Preparation
Set a steamer basket in a large saucepan. Fill with enough water to come just below basket. Bring to a boil; place potatoes in basket, and reduce to a simmer. Cover, and steam until tender, 15 to 20 minutes.
Meanwhile, in a large bowl, whisk together oil, mustard, and vinegar. Add celery, scallions, and hot potatoes, and season with salt and pepper; toss to combine. Cool to room temperature, tossing occasionally, about 1 hour.