Radicchio and Watercress Salad with Parmesan Curls Recipe

2 tablespoons white-wine vinegar
1/2 teaspoon Dijon-style mustard
2 teaspoons finely chopped fresh parsley leaves
1/3 cup extra-virgin olive oil
2 bunches of watercress, trimmed, washed well, spun dry, and separated into small sprigs
2 small heads of radicchio , shredded fine, washed well, and spun dry
3 scallions, sliced
6 ounces Parmesan at room temperature, shaved into curls with a vegetable peeler

In a small bowl whisk together the vinegar, the mustard, the parsley, and salt and pepper to taste, add the oil in a stream, whisking , and whisk the dressing until it is emulsified. In a large bowl toss together the watercress, the radicchio, and the scallions, pour the dressing over the salad greens, and toss the mixture well. Transfer the salad to a serving bowl and arrange the Parmesan curls on top.