Shrimp and Grapefruit Spinach Salad

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. Looking for more quick and easy recipes? Check out our quick family-favorites, fast dinners for weeknights, and healthy recipes for less than $3 a serving.