Slice the potatoes into 3mm / ⅛ inch slices ideally using a mandolin. Slice the onions, again it is best with the mandolin, into the thinnest slice available.

Spray an ovenproof dish with Spray2Cook. Add a layer of potatoes followed by a layer of onions (before seasoning with salt and pepper), then ham, then tomatoes and finally cheese. Pour over stock to just cover. Press the contents flat with a fish slice. Repeat the process and then - end up with just potatoes as the top layer and do not cover with stock.

Microwave the dish for 7 minutes. Test the top layer to ensure it is soft enough for the point of a knife to easily slide in – if not cook further in 1 minute bursts until it is. Carefully remove the hot dish from the microwave and spray the top layer of potato with Spray2Cook. Place the dish under a hot broiler / grill until to top layer of potato is turning brown. Serve the boulangère pie dish onto a heatproof plate and enjoy direct from the dish.