To prepare the cure and beef, transfer coriander, peppercorns, shallots, garlic, salt and sugar to a large container and add the beef loins to cure for 1 hour, turning occasionally.
Preheat the oven to 375̊F. Heat the olive oil in a skillet over medium heat until lightly smoking. Remove the beef from the cure and scrape clean. Sear on all sides in the skillet. Transfer to an ovenproof baking dish and cook in the oven for about 7 minutes until medium. When the beef is done, remove from the oven and let rest for 3 to 5 minutes. Slice the loin and serve.