Nutrition per serving may change if servings are adjusted.
4 small skinless, boneless chicken breast halves (about 1- ¼ pounds total)
Nonstick cooking spray
3 cups arugula
2 cups shredded baby spinach leaves
2 pink grapefruit, peeled and sliced crosswise
½ medium fennel bulb, thinly sliced
1 avocado, halved, seeded, peeled, and sliced
2 tablespoons grapefruit juice
1 tablespoon Champagne vinegar
1 tablespoon olive oil
¼ teaspoon salt
¼ teaspoon ground black pepper
Place each chicken breast half between two pieces of plastic wrap. Using the flat side of a meat mallet, pound chicken lightly until ¼ to ½ inch thick. Remove plastic wrap.
Lightly coat a panini griddle, covered indoor electric grill, or large nonstick skillet with cooking spray. Heat over medium heat or heat according to manufacturer's directions. Add chicken. If using griddle or grill, close lid and grill about 4 minutes or until chicken is no longer pink. (If using skillet, cook chicken about 8 minutes or until chicken is no longer pink, turning once.)
Arrange chicken breast halves, arugula, spinach, grapefruit, fennel, and avocado on four serving plates.
To prepare Champagne Vinaigrette: Whisk together grapefruit juice, vinegar, olive oil, salt, and black pepper in a small bowl. Drizzle salads with vinaigrette.