WANTED: Sizzling Fillet Steak recipe

Each time I go to my favourite Japanese restaurant I can't help getting the sizzling fillet steak in a special sauce and each time I have it, I wish I could make this at home.
This is the website to my favourite and well worth the visit if your in the area of Plymouth, UK:
http:/www.yukisan.co.uk/
Does any one know of a recipe that I can re-create this at home? All I know is that it comes out on a seriously hot cast-iron plate, with a sauce you can die for. I have asked or searched for any recipes (even basic one's) without any success and I would love it, if someone could post some recipes on how do make this dish.
Please help me...