Grilled Chicken Cordon Bleu

4 boneless, skinless chicken breast halves
4 oz. Thinly sliced deli ham
4 oz Swiss cheese, cut into 4 blocks
Dijon mustard
Salt and black pepper
 
Preheat grill to medium-high. Cut a pocket into each breast by inserting a knife blade into the wide end. Sweep the blade back and forth, cutting the opening larger, being careful not to cut through the end, top, or bottom. Wrap a slice of ham around each block of cheese and insert into the pockets. Coat each breast with Dijon and season with salt and pepper. Grill chicken, covered, 5 minutes each side.
 
Drizzle if desired with the following mixture, whisked together:
2 Tablespoons rice vinegar
1 Tablespoon Dijon mustard
1 Tablespoon honey
2 Tablespoons olive oil