- Preheat the oven to 180°C.
- Butterfly the chicken breasts and bash them, using a meat tenderiser (or a rolling pin) gently bash them as thinly as you can. It helps to place clingfilm on either side of the breast as you do this.
- Get two equal sized loaf tins and line them with clingfilm. Lay two chicken breasts at the bottom of each - the edges should be larger than the tin so you can fold them over a little bit. Top with ham and emmental and season, then repeat around 3 or four times in each tin, layering up and folding the sides over the ham and cheese as you go. Finally, take one of the tins and stick it top down on top of the other to create your massive chicken brick. Wrap in clingfilm and freeze for around two hours - don't be tempted to freeze the whole thing or it'll take forever to cook.
- When it's hardened up, place your flour, eggs and panko in some deep sided baking trays. Carefully cover the whole thing in flour then shake off any excess. Dip it in the egg, letting it drip back into the bowl, and finally into the panko. If there are any patches missing then paint them with egg and press the panko into place.
- In a wide, heavy bottomed skillet heat the vegetable oil to 170°C and carefully fry the chicken brick on all sides until golden. Place on a baking tray and bake until the internal temperature reads 71°C.
- Meanwhile, make the cheese sauce - heat the butter until foaming then add the flour and cook for 30 seconds or so, then gradually whisk in the milk. Take off the heat and add the cheese a handful at a time until you've got a smooth sauce - add dijon and salt (if necessary).
- Serve the giant chicken cordon bleu in slices, with chips, covered in cheese sauce