2Mix mustard, thyme, 1/2 tsp salt and the cayenne pepper in a medium bowl. Add the chicken breasts, turn to coat completely, set aside.
3In medium shallow bowl, combine parmesan cheese and panko breadcrumbs. Dredge the chicken pieces in panko mixture, pressing coating into the meat.
4Put chicken on a rack over a baking sheet. Spray chicken with a quick burst of cooking spray; and place in middle of the oven. Bake until chicken is golden brown, and cooked through, about 20 minutes.