Trim and season the beef. If there’s a layer of heavy connective tissue on the roast, trim it off with a sharp knife (many butchers will have already removed this). Avoid removing too much external fat, as a little fat will baste the meat as it roasts, keeping it flavorful and juicy. If the surface feels wet, pat it dry with paper towels. Season the meat all over with the pepper and salt, rubbing so that all the seasonings adhere. Let the meat sit, uncovered, at room temperature for 1 to 2 hours before roasting. If seasoning it further ahead than that, cover it loosely with plastic wrap and refrigerate for up to 24 hours.
Heat the oven. Position a rack near the center of the oven and heat to 400 degrees (375 degrees convection).
Roast the meat. Fit a shallow roasting pan with a flat rack if you have one. (If you don’t, use the makeshift aluminum foil rack described on page 46.) Place the tri-tip fat side up on the rack and roast until the internal temperature of the thickest part of the roast, measured with an instant-read thermometer, reaches 120 degrees for rare, 125 to 130 degrees for medium-rare, 135 degrees for medium. Start checking after about 25 minutes; medium-rare (my preference) will take 30 to 35 minutes.
Rest. Transfer the roast to a carving board, preferably with a trough and let it rest for about 10 minutes. Expect the temperature to rise about 7 degrees as the meat rests.
Carve and serve. Carve across the grain into thin slices and serve with chimichurri, if desired.
Recipe courtesy of All About Roasting by Molly Stevens/W.W. Norton & Company, 2011.