Heat oven to 425°F. Spray 15x10x1-inch pan with cooking spray. In small bowl, mix mustard, Italian dressing and garlic.
In another small bowl, mix bread crumbs, parsley, thyme and pepper. Stir in butter.
Spread mustard mixture on both sides of each chicken breast; place in pan. Spoon bread crumb mixture evenly on top of chicken; press in firmly.
Bake uncovered 15 to 20 minutes or until juice of chicken is clear when center of thickest part is cut (170°F). If desired, cut chicken breasts diagonally into slices before serving.