Lay a piece of plastic wrap on top of a cutting board and place the chicken breast in the center. Fold the plastic wrap over the chicken breast and pound the meat with a rolling pin or meat tenderizer until evenly thin. Unfold the plastic wrap and season the chicken with salt and pepper.
Lay 4 slices of Swiss cheese on the flattened chicken breast, followed by 3 slices of ham and 4 more slices of Swiss cheese.
Roll up the chicken breast, tightly seal it in plastic wrap, and refrigerate for 30 minutes.
After 30 minutes, remove the plastic wrap from the stuffed chicken roll and heat some cooking oil in a pan. Coat the stuffed chicken roll in flour, egg, and bread crumbs and fry in hot oil until golden brown.
For the bechamel sauce, melt the butter in a pot over medium heat and briefly sweat the garlic. Whisk in the flour and the milk and season with salt and pepper. Add the mustard and parmesan cheese to the pot, mix well, and let the sauce simmer.
Cut the chicken cordon bleu roll into uniform slices, pour bechamel sauce on top, and garnish with fresh chopped parsley.