In a food processor, puree butter, pitted olives, and anchovy filet until smooth. Adjust seasonings to taste with salt and freshly ground black pepper.
Transfer olive butter to a sheet of plastic wrap. Roll plastic wrap around butter and twist ends to force butter into a log shape; refrigerate.
In a large baking dish, combine thyme, parsley, oregano, rosemary and pepper. Gradually stir in olive oil. Add steaks and rub with marinade. Cover and refrigerate 4 hours or overnight.
Remove olive butter from refrigerator about an hour before grilling steaks.
Light your grill and grill steaks for 5 minutes per side or until steaks reach desired doneness.
Remove steaks to a platter, topping each steak with a slice of olive butter. Tent with foil and let rest for 5 minutes.
Transfer steaks to individual dinner plates and serve with a small slice of olive butter.