Prep Time: 10
Cook Time: 7
Serves: Serves: 2
Preheat broiler. Place chicken between sheets of plastic or wax paper; pound evenly to 1/4-inch thickness. Place chicken on rack of broiler pan. Sprinkle lightly with salt and pepper to taste. Broil 4 inches from heat source for 3 minutes.
Meanwhile, combine mayonnaise and pesto; spread half of mixture over toast slices. Turn chicken over; spread remaining mixture over chicken. Return to broiler; broil until chicken is cooked through, about 3 minutes. Place cheese over chicken; continue to broil until cheese melts, about 1 minute.
Arrange spinach and roasted peppers over 2 slices of toast; top with chicken and close sandwiches with remaining toast, pesto-sides down.