- 4 teaspoons Sherry vinegar
- 1 tablespoon minced shallot
- 1/2 teaspoon Dijon mustard
- 1/2 teaspoon salt
- 1/4 teaspoon black pepper
- 1/4 cup extra-virgin olive oil
- 2 teaspoons finely chopped fresh tarragon
- 1/2 lb frisée (French curly endive), torn into bite-size pieces
- 1 head Boston lettuce (1 lb), torn into bite-size pieces
- 1 bunch arugula (1/2 lb), coarse stems discarded
- 1 bunch watercress (1/2 lb), coarse stems discarded
- Whisk together vinegar, shallot, mustard, salt, and pepper in a small bowl, then add oil in a slow stream, whisking until emulsified. Whisk in tarragon.
- Toss greens with dressing in a large bowl and season with salt and pepper.