Chicken Florentine

3 tbsp zesty Italian dressing
4 cups lightly packed spinach leaves
4 small boneless skinless chicken breast halves (1 lb)
8 thin slices smoked ham
1 cup shredded Swiss cheese

Heat 1 tbsp dressing in large oven proof skillet on medium heat. Add spinach; cook and stir 1 minutes or just until spinach is wilted. Remove from skillet; cover to keep warm. Add remaining 2 tbsp dressing and the chicken to skillet; turn chicken over to evenly coat both sides with dressing. Cook 5 to 6 minutes on each side or until chicken is cooked through. Top evenly with ham and cheese; cover. Reduce heat to low; cook 1 to 2 minutes until cheese is melted, or place under a broiler to brown. Spoon spinach mixture evenly onto 4 plates; top each with a chicken breast.