Step 2) Heat butter and oil in large skillet and add chicken. Cook 5 to 7 minutes, turning once, until chicken is browned. Remove chicken to a platter. Sauté mushrooms in skillet, stirring often, for about 5 minutes. Add marina sauce and mix well. Place chicken breasts on top of sauce; top each with slice of cheese. Cover and cook over low heat for 5 to 8 minutes, until chicken is cooked through.