Put the olive oil and the whole garlic cloves in a large skillet or sauté pan and turn on the heat to medium high. Cook, stirring two or three times, until the garlic becomes colored a pale gold. Turn off the heat and add the rosemary, turning it over a few times.
Turn on the heat under the cast-iron skillet or the stove-top grill to very high. When the pan or grill surface is very hot put on the meat, which should sizzle instantly and quickly begin to smoke. Cook it for 2 or 3 minutes until it is a very dark brown on one side; then turn it over, sprinkle with salt, and do the other side.
Transfer the steaks to a cutting board and cut them on an angle into slices about ½inch thick. The meat should be quite, quite rare.
Turn on the heat to medium high under the pan containing the oil, garlic, and rosemary. As soon as the oil begins to heat up, put in the steak slices together with any juices they may have shed on the cutting board. Cook for about 1 minute at very lively heat, turning the meat over frequently and adding liberal grindings of black pepper.
Transfer the meat to a warm platter and pour over it all the oil and juices in the pan, but hold back the rosemary and garlic. Serve piping hot.