Ingredients

3 pink grapefruit

3 tablespoons wine vinegar

2 teaspoons Dijon mustard

Salt and pepper

1/2 cup plus 1 tablespoon vegetable oil

1 1/2 pounds large shrimp, peeled and deveined

1 1/2 pounds spinach, stems trimmed and leaves washed well (about 3 1/2 quarts)

1/2 red onion, thinly sliced

Preparation

With a sharp knife, peel the grapefruit, removing all the bitter white pith. Slice about 3/8 inch thick.

In a large bowl, whisk together the vinegar, mustard, and 1/8 teaspoon each salt and pepper. Drizzle in 1/2 cup of the oil, whisking to combine.

Season the shrimp with 1/2 teaspoon salt and 1/8 teaspoon pepper. In a large nonstick skillet, heat the remaining tablespoon oil over medium heat. Add the shrimp, and cook, turning once, until pink, about 3 minutes per side.

Add the grapefruit, cooked shrimp, spinach, and onion to the vinaigrette in the large bowl. Toss well. Serve at once.