Heat a griddle pan or large non-stick frying pan until very hot. Meanwhile, brush the steaks each side with a little of the oil. When the pan is hot, add the steaks and cook for 1 1/2 minutes on each side (a little more or less, depending on thickness of the steaks) for medium-rare. Remove the steaks to a rack placed over a plate in a warm place to catch the juices, and season well.
Combine the remaining olive oil with the vinegar and some seasoning in a small bowl. Arrange the rocket leaves on serving plates. Cut each cherry tomato in four and arrange over the rocket.
When the steaks have rested for at least 5 minutes, tip any juices beneath them into the olive oil dressing and stir. On a board, cut each steak into slices about 5mm thick and arrange the slices on the rocket, then add any juice from the cutting board into the dressing and sprinkle it over each plate. Shave the Parmesan over the steaks to serve.