In a mixing bowl, combine soy sauce, fish sauce, brown sugar, minced garlic, chopped lemongrass, and black pepper to create a flavorful marinade. Cut the beef sirloin into thin slices and place them into the marinade, ensuring each piece is evenly coated. Cover the bowl with plastic wrap and refrigerate for at least 4 hours or overnight for maximum flavor absorption.

Rinse the jasmine rice under cold water until the water runs clear. In a pot, combine the rinsed rice with water using a 2:1 ratio—two cups of water for every cup of rice. Bring it to a boil, then reduce the heat to low, cover the pot, and simmer for about 18-20 minutes, or until the water is completely absorbed and the rice is tender.

While the rice is cooking, take the marinated beef out of the refrigerator and let it come to room temperature for uniform grilling. Preheat your grill to medium-high heat, aiming for around 400°F (200°C).

Once the grill is ready, place the marinated beef slices directly onto the grill grates. Grill each side for about 3–4 minutes, keeping an eye on them for a good char.

After grilling, let the beef rest for a few minutes to lock in those juices, then slice it into bite-sized pieces if necessary. Serve the grilled beef over a generous bed of jasmine rice, garnishing with optional pickled vegetables and fresh herbs for added flavor. Don’t forget a small bowl of nuoc cham on the side.