After long curiosity, finally I had the chance to make this. It started with my husband accidentally passing by the meat section in the supermarket. He saw the sign "wagyu beef promo" and then decided to take a closer look. The promo sign didn't lie, it was really cheap. Then we bought 3 slices of wagyu beef (about 750 grams total), all only cost no more than Rp75,000. Normally, it cost more than Rp100,000 per portion (about 250 gr) in the restaurant. So, I think I did a good job on this. The meat quality was also good, still red and fresh, with georgeous white marbling fat.
Wagyu literally means Japanese cow. The cows have unique characteristics that produce high quality beef that is famous around the world. When grilled, the marbling fat will melt down and leave the meat so tender and succulent. And the best way to grill is medium well or almost well done, when the center part of the steak is still freshly pink or has slightly red streak. Don't worry about the seasoning. I just use salt, pepper, and paprika.
Rub the meat with salt, ground white and black pepper, and paprika powder. Put the meat in the fridge and let it rest for about 30 minutes or 1 hour. I use non-stick grill pan. This pan will make the char effect on your meat. Just rub the pan slightly with oil, and heat it with medium heat. When the pan is hot, grill the steak. Takes 2 minutes to grill each side of the steak, this will make nice char and the perfectly medium-well cooked meat.
To make the sauce, just melt the butter in the pan with low heat to dissolve the crust and the spices. Scratch gently with a wooden or silicone spoon. Be careful, not to ruin the non-stick layer of the pan. The sauce making only takes about 2 minutes, so the butter won't be burnt. Then pour the sauce onto the steak, and serve it with fried sliced potatoes and your favorite greens. Or anything you want.