Scatter the garlic and rosemary over the top of lamb racks, and drizzle with the olive oil. Leave for 1 hour or more.
Preheat the oven to 200°C.
Season the lamb generously with salt and pepper.
Heat the pan over a medium high heat and fry each side of the racks 1-2 minutes until golden brown.
Put racks in a large roasting tin, roast for 16-20 minutes or desired doneness is reached.
Transfer the lamb to a warmed plate, cover loosely with foil, and allow to rest in a warm place for about 5 minutes before carving.
Carve into cutlets and serve.