1/4 cup olive oil, plus more for oiling the grill
4 medium garlic cloves, finely chopped
1 tablespoon finely chopped rosemary leaves
Juice of 1 medium lemon
1 (2-pound) beef tri-tip roast
Freshly ground black pepper
Argentine Chimichurri Sauce (see recipe below)
Place the measured oil, garlic, rosemary, and lemon juice in a small, nonreactive bowl and stir to combine; set aside.
Pat the tri-tip dry with paper towels. Rub a generous amount of salt and pepper all over the tri-tip, followed by the reserved marinade. Transfer the tri-tip to a baking sheet and let sit at room temperature while you prepare the grill.
Fill a medium-sized chimney starter with lump charcoal (about 5 to 6 quarts). Crumple 2 to 3 pages of newspaper and place in the bottom of the chimney starter. Set the starter on the charcoal grate of the grill and light the newspaper. After about 10 minutes the coals should be red, with flames coming out of the top of the chimney starter. (If the charcoal doesn’t light, you may have put too much newspaper under the starter—the flames need air to spread—so repeat lighting the newspaper.)
Place the lit charcoal on one side of the grill, forming a mound. Place the cooking grate over the charcoal and let the grill preheat for about 15 minutes (the charcoal should have turned white and ashy by this point).
Rub the grill grate with a towel dipped in olive oil. Place the tri-tip on the grill over the coals, cover the grill, and cook for 5 minutes. Rotate the tri-tip 90 degrees (keeping the meat over the coals), cover, and grill until the underside is deep brown and grill marks have appeared, about 5 to 6 minutes more.
Flip the tri-tip and continue grilling over the coals, rotating 90 degrees once during the cooking time, until the meat is deep brown, grill marks have appeared, and the tri-tip has reached an internal temperature of 125°F (for medium rare) on an instant-read thermometer, about 10 to 12 minutes total.
Transfer the meat to a cutting board, tent loosely with foil, and let rest for 10 minutes. Slice against the grain and serve with chimichurri.
Argentine Chimichurri Sauce
2 cups packed fresh Italian parsley leaves
4 medium garlic cloves, peeled and smashed
1/4 cup packed fresh oregano leaves (or 4 teaspoons dried oregano)
1/4 cup red wine vinegar
1/2 teaspoon red pepper flakes
1/2 teaspoon kosher salt
Freshly ground black pepper
1 cup extra-virgin olive oil
Place parsley, garlic, oregano, vinegar, red pepper flakes, salt, and pepper (to taste) in the bowl of a food processor fitted with a blade attachment. Process until finely chopped, stopping and scraping down the sides of the bowl with a rubber spatula as needed, about 1 minute total.
With the motor running, add oil in a steady stream. Scrape down the sides of the bowl and pulse a few times to combine. Transfer sauce to an airtight container and refrigerate at least 2 hours or up to 1 day to allow the flavors to meld. Before serving, stir and season as needed. The chimichurri will keep in the refrigerator for up to 1 week.
Recipe shared from: http://www.chow.com/recipes/28390-argentine-grilled-tri-tip