Two-potato salad with mustard dressing

TWO-POTATO SALAD WITH MUSTARD DRESSING

1 pound boiling potatoes (preferably yellow-fleshed), quartered lengthwise and cut crosswise into 3/4-inch pieces
1 pound sweet potatoes, quartered lengthwise and cut crosswise into 3/4-inch pieces
1 tablespoon white-wine vinegar
2 tablespoons OR more Dijon-style mustard
Salt and pepper
1/4 cup olive oil
1/4 cup finely chopped onion
1/4 cup finely chopped red bell pepper
2 tablespoons OR more finely chopped sweet gherkin

In a steamer set over boiling water, arrange the boiling potatoes, top them with the sweet potatoes, then steam, covered, for 10 to 12 minutes, or until the potatoes are just tender. Transfer potatoes to a bowl and let cool; then peel if necessary.

In another bowl, whisk together vinegar, mustard and salt and pepper to taste. Add oil in a stream, whisking, and whisk dressing until it is emulsified. Add dressing to the potatoes along with onion, bell pepper and gherkin and combine salad well.

Makes 6 servings. From Gourmet magazine