To make the wasabi sauce, mix the sour cream and wasabi in a bowl; set aside.
For the Garlic-Soy Sauce Marinade: Whisk together the soy sauce, garlic, olive oil and black pepper in a small bowl. This marinade can keep in the refrigerator for up to 2 weeks. Just mix again before using it.
Pour the marinade into a baking dish. Lay the steaks in the marinade, and flip them 4 times to generously coat all over. Marinate the steaks for 10 minutes.
Preheat a grill with a hot zone and a medium zone. Grill the steaks, covered, about 8 minutes for medium-rare this way: Start on hot heat for 1 minute, then shift the steaks to medium heat. After about 3 minutes, juices will begin to appear on top of the steaks. Turn and repeat the two-zone grilling on the other side. When the steaks are ready, they'll be browned and juicy on the surface, and the bone will stick out a bit, as the meat around it has shrunk. Let the steaks rest for about 3 minutes before serving with the wasabi sauce.