Can be prepared in 45 minutes or less.

Ingredients

　　2 1/2 tablespoons Sherry vinegar (available at specialty foods shops) or white-wine vinegar

　　2 teaspoons Dijon-style mustard

　　1/2 cup olive oil

　　5 heads of Bibb lettuce, leaves torn into bite-size pieces, rinsed, and spun dry (about 10 cups)

　　2 large bunches of watercress, coarse stems discarded and the leaves rinsed and spun dry (about 5 cups)

　　2 cups fresh mint leaves, rinsed and spun dry

　　In a bowl whisk together the vinegar, the mustard, 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 the greens with the dressing.