Preheat the oven to 230C/450F/Gas 8.
Cook the potatoes in boiling salted water for 15 minutes or until just tender, then drain.
Place on a baking tray and squash each potato with a potato masher. Drizzle with olive oil, scatter with caraway seeds, thyme, salt and freshly ground black pepper and bake in the oven alongside the tomatoes for 30 minutes or until very crisp and golden brown, removing the tomatoes when soft.
For the steaks, mix the sea salt, pepper and rosemary together on a plate. Brush the steaks with olive oil and press into the seasoning on both sides.
In a frying pan, briskly sear the steaks on one side until well-browned, then turn once and cook briefly for a medium rare result. Set aside to rest.
To serve, toss the rocket with the olive oil. Slice the steak into fingers, loosely arrange over a large platter, strew with the roasted tomatoes and lemon quarters, and serve with the potatoes and rocket.