French Onion Chicken Sandwich
1 T. extra virgin olive oil
1 large white onion, thinly sliced
1 t. granulated sugar
2 boneless, skinless chicken breasts, halved crosswise and pounded to 1-inch thickness, if necessary
Nonstick cooking spray
4 slices Swiss cheese
4 hamburger buns
2 c. baby spinach
In large skillet, heat oil over medium heat. Add onion and sugar; cook 25 minutes or until onions are deeply caramelized, stirring frequently. This step can be done up to 3 days in advance. Re-warm onions in microwave or in a small pan on grill before proceeding.
Preheat grill for direct grilling over medium-high heat. Spray chicken with nonstick spray. Transfer chicken to hot grill rack; cover and cook 10 minutes or until chicken loses its pink color throughout and internal temperature reaches 160°, turning once.
Place cheese slices on chicken pieces. Cover and cook 1 to 2 minutes or until cheese is melted and golden brown. Build sandwiches using hamburger buns, spinach, chicken and caramelized onions.