Grassfed beef cooks differently than conventional (grain-fed) beef.
It has less saturated fat and more healthful poly-unsaturates and mono-unsaturates, plus it contains more "conjugated linoleic acid" or CLA, another so-called good fat, than is present in grain-fed beef. The different fatty acids change the cooking environment. The unsaturated fats have a lower boiling point which heats the meat more quickly. It is easy to overcook unless you pay close attention, and should be cooked to a lower internal temperature because it will keep cooking even off the heat. A roast's temperature will rise as much as 10 degrees in the 15 minutes it rests before you carve it. If cooked past medium-rare, it dries out and can become tough -- unless, as with a low-temperature braise, it's cooked long enough to tenderize the meat. Because it comes from cows not raised in feedlots, the likelihood of bacteria contamination is extremely low; it's much safer to eat it rare than it is conventional beef.
Start off by searing the steaks on their fatty sides, standing them on edge in a cast-iron skillet. This method renders some of the fat into the pan and flavors the meat. Sear the meat in the fat. Turn down the heat and flip the steaks every minute or so. You want to flip them often so the juices don't rise to the top and subsequently evaporate when they hit the pan. Carmelization will continue to occur at medium heat, which is why you don't need to blast them for the entire duration. Continue to cook the steaks in this manner until they are done to your liking. Place them on a cooling rack after they are removed from the pan with a plate underneath to catch the drippings. If the steak is placed directly on a plate, the bottom surface that you've just so carefully caramelized, steams from the residual heat and softens up. By putting the steak on a cooling rack, both sides cool evenly and stay crisp.
When eating the steak, keep in mind the type of cut and the way the muscle runs. For a t-bone, cut away the entire muscle from the bone, and then thinly slice it across the grain. Thinner slices make for a tenderer mouth-feel. Cutting random chunks from the steak will only yield big uneven pieces that will be obviously harder to chew. A really sharp steak knife will prevent any shredding, caused by a back and forth sawing motion. One long continuous slice will yield the tenderest eating experience.