Here's how:
1 Trim the chicken of excess fat and sinew. Using a sharp knife, cut into the thickest section of each fillet without cutting right through. Open the fillet out flat and season with salt and freshly ground black pepper.
2 Place a slice of cheese and ham on one side of each fillet. Fold the remaining half of the fillet over to enclose the filling.
3 Carefully coat each fillet with hour, then shake off the excess. Dip into the egg, then coat with the breadcrumbs. Place on a foil-lined baking tray. Place, covered, in the refrigerator for 30 minutes.
4 Heat the oil in a medium heavybased pan. Add the chicken and cook in two batches over medium heat for 4 minutes each side, or until the chicken is golden and cooked through. Add more oil between batches if necessary. Serve the chicken immediately.

Source: The Complete Chicken Cookbook (Murdoch Books)