4 boneless, skinless, chicken breasts
2 oz. (50 g) ham, thinly sliced, cut into 1/2 inch strips
2 oz. (50 g) Gruyere cheese, thinly sliced, cut into 1/2 inch strips
2 egg whites
1/4 cup buttermilk
1 tbsp Dijon mustard
2/3 cup fine dry bread crumbs
1/4 cup Parmesan cheese
1/2 tsp freshly ground pepper
Mix the seasonings in a small bowl.
To butterfly each chicken breast: Place on cutting board. With blade of sharp knife parallel to counter, make a horizontal slit along thinner, long edge of each breast, cutting nearly through to opposite side. Open breast so it lies flat, hinged at center. Place one quarter of ham and Gruyere on half of each breast. Close chicken carefully. Set aside. Repeat with remaining breasts.
In medium bowl, combine egg whites, buttermilk and mustard. Whisk until creamy. In shallow dish combine bread crumbs, Parmesan and pepper.
Carefully dip each piece of chicken in crumb mixture, then egg white mixture and back in crumb mixture. Set on greased rack on baking sheet. Bake at 400°F 30 - 35 minutes or until golden and thoroughly cooked and no trace of pink.