Preheat oven to 400° F.
Place chicken between 2 pieces of wax paper and pound to 1/4-inch thickness.
Spread mustard evenly down center of each breast half.
Sprinkle with thyme.
Top with ham slice and 1/2 slice of cheese.
Roll up jellyroll style, tucking in sides of chicken to seal.
Secure with skewers or large wooden toothpicks.
Combine breadcrumbs and Parmesan cheese in a shallow dish.
Brush each chicken breast with melted butter
Roll in crumb mixture.
Place in 9" x 9" baking pan.
Bake at 400° F. for 10 minutes.
Reduce oven to 350° F. and continue baking 20-25 minutes, or until chicken is tender.
Remove skewers and serve immediately.