How to Make It
In a mortar or using the side of a large knife, crush the garlic with 2 tablespoons of the salt to a paste. Stir in the peppercorns, rosemary, sage and the remaining salt. Spread the mixture on a plate and let stand overnight at room temperature, stirring occasionally, until dry and crumbly.
Generously rub the salt mixture all over the steak. Let stand at room temperature for 4 hours or refrigerate for 6 hours.
Preheat the oven to 425°. Light a grill or preheat a grill pan. Scrape the salt from the steak and brush lightly with oil; grill over high heat for 10 minutes, turning, until crusty all over. Transfer the steak to a shallow roasting pan and roast for 10 minutes, turning once or twice, until an instant-read thermometer inserted into the thickest part of the meat registers 125°. Transfer to a cutting board and let rest for 10 minutes. Slice the meat from the bone and serve.