- 1 red onion
- 3 tablespoons cider vinegar
- 1 1/2 teaspoons sugar
- 1 teaspoon powdered mustard or 2 teaspoons Dijon mustard
- 1/2 cup extra-virgin olive oil
- 1 pint vine-ripened cherry tomatoes
- 4 cups mixed crunchy sprouts such as pea and lentil
- 3/4 pound baby spinach
- available at specialty produce markets and some natural foods stores and supermarkets
- Halve onion lengthwise and very thinly slice crosswise. In a bowl cover onion with cold water. Chill onion in water 30 minutes.
- In a bowl whisk together vinegar, sugar, mustard, and salt and pepper to taste and add oil in a slow stream, whisking until emulsified. Dressing may be made 2 days ahead and chilled, covered.
- Drain onion well in a colander and pat dry. Quarter tomatoes and in a large bowl toss with onion, sprouts, spinach, and dressing.