To cook the steak, Preheat a cast iron pan over medium-high heat. Place EVOO into pan.
Spread sugar on a plate and press Wagyu Steaks into it. Place steaks, sugar side down into hot pan. Cook for 3-4 minutes, turn over and cook 2-3 minutes or to taste.
Pour soy sauce over steaks, place lid on pan and remove from heat. Rest for 3 minutes before removing steak from the pan and rest on a board for 5-10 minutes. Slice thinly and serve with Truffled Mushroom Sauce.
To make the Truffled Mushroom Sauce, Heat a cast iron pan over low-medium heat. Add butter and EVOO and wait till the butter melts. Add mushrooms and garlic to the pan, with salt and pepper and cook slowly for 10 minutes, stirring occasionally.
Increase the heat and add 70g of the wine, sherry and sherry vinegar. Cook for at least 10 minutes, stirring occasionally, until the mushrooms have caramelised and most of the liquid is reduced.
Add the remaining 100g of wine, oregano and parsley and cook stirring for 5 minutes, then add cream and stir to combine.
Shave fresh truffle over the sauce right before serving.
This sauce is fantastic on chicken or a risotto as well!