- 1 tablespoon extra-virgin olive oil
- 1 tablespoon sherry vinegar
- 1/4 teaspoon freshly ground black pepper
- 1/4 teaspoon Dijon mustard
- 1/8 teaspoon salt
- 4 cups baby arugula
- 1/3 cup vertically sliced red onion
Combine first 5 ingredients in a large bowl; stir with a whisk. Add arugula and onion; toss well.