teaspoons kosher salt
medium garlic cloves , minced or pressed through garlic press (about 2 tablespoons)
tablespoons minced fresh rosemary leaves
tablespoon ground black pepper
(3- to 4-pound) top sirloin roast (see note)
Vegetable oil for cooking grate
(13 by 9-inch) disposable aluminum roasting pan
1. Combine salt, garlic, rosemary, and pepper in small bowl. Sprinkle all sides of roast evenly with salt mixture, wrap with plastic wrap, and refrigerate for 18 to 24 hours. 2. Open bottom grill vents fully. Light large chimney starter half filled with charcoal (3 quarts, about 50 briquettes) and allow to burn until coals are fully ignited and partially covered with thin layer of ash, about 15 minutes. Arrange all coals over one-third of grill. Position cooking grate over coals, cover grill, and heat grate until hot, about 5 minutes. Scrape grate clean with grill brush. Dip wad of paper towels in vegetable oil; holding wad with tongs, wipe cooking grate. 3. Place roast over hot part of grill and cook until well browned on all sides, about 10 minutes. Meanwhile, punch fifteen 1/4-inch holes in center of aluminum roasting pan in area roughly same size as roast. Once browned, place beef in pan over holes and transfer pan to cool side of grill. Open lid vents halfway and cover grill, positioning vents over meat. 4. Cook roast, rotating pan 180 degrees halfway through cooking and removing lid as seldom as possible, until instant-read thermometer inserted into thickest part of meat registers 125 degrees for medium-rare or 130 degrees for medium, 40 to 60 minutes. Transfer meat to wire rack set on rimmed baking sheet, tent loosely with foil, and rest for 20 minutes. Transfer meat to carving board and cut across grain into thin slices. Serve immediately.