Thai-Dipped Beef Tri Tip

In a large mixing bowl, combine the bruised and chopped lemongrass, fish sauce, brown sugar, rice wine vinegar, crushed garlic, grated ginger, soy sauce, grated onion, vegetable oil, ground coriander, ground cumin, ground turmeric, and cayenne pepper. Whisk until thoroughly mixed. (5 minutes)

Using a fork, poke both sides of the tri-tip roast numerous times to allow the marinade to deeply penetrate the meat. Add the tri-tip to the marinade and toss to coat thoroughly. Cover the bowl with plastic wrap and refrigerate for at least 2 hours, or up to 12 hours, occasionally flipping the roast and continuing to poke it with a fork to enhance marinade absorption. (2-12 hours)

Remove the roast from the marinade, allowing any excess to drip off. Place the roast on a paper-towel-lined tray to drain briefly. Reserve the marinade for basting. (5 minutes)

Preheat an outdoor grill to 325 degrees F (165 degrees C), using indirect heat. Lightly oil the grill grate to prevent sticking. (10 minutes)

Place the tri-tip roast on the preheated grill over indirect heat, covered. Baste with the reserved marinade and turn the roast occasionally, cooking for approximately 35 to 45 minutes, or until an instant-read thermometer inserted into the center of the roast registers 130 to 135 degrees F (54 degrees C) for medium-rare. (35-45 minutes)

Once the tri-tip reaches the desired temperature, transfer it to a cutting board. Allow the roast to rest for at least 20 minutes before slicing against the grain. This allows the juices to redistribute, resulting in a more tender and flavorful final product. (20 minutes)

While the roast rests, heat any remaining marinade in a saucepan over medium heat. Bring to a boil, then reduce heat and simmer for 1 to 2 minutes to ensure it is safe to serve as a sauce. (5 minutes)

Slice the rested tri-tip against the grain and serve immediately, accompanied by the simmered Thai-inspired sauce.