For stuffing, coat a large nonstick skillet with cooking spray. Heat skillet over medium heat. Add mushrooms and garlic; cook until mushrooms are tender. Stir in roasted pepper and marjoram. Remove from heat.
Cut a horizontal slit in the thickest portion of each chicken piece, forming a pocket. Place a slice of cheese and some of the stuffing in each pocket. Secure with wooden toothpicks.
In a large skillet cook chicken in hot oil over medium heat about 4 minutes or until light brown, turning once. Pour broth and wine into skillet. Bring to boiling; reduce heat. Simmer, uncovered, about 8 minutes or until chicken is no longer pink (170 degree F). Transfer chicken to a serving platter.
Strain pan juices; measure juices and return to skillet. If necessary, boil gently, uncovered, until liquid is reduced to 3/4 cup. In a small bowl combine water and cornstarch; stir into liquid in skillet. Cook and stir until thickened and bubbly. Return chicken to skillet; cook about 2 minutes more or until heated through. Remove toothpicks from chicken. Sprinkle with parsley. Makes 4 servings.