Combine the lime juice, fish sauce, sugar, pepper.
On a plate, arrange the sirloin on a single layer and marinate in the lime juice mixture for 10 minutes, ensuring all the meat is covered. Transfer to fridge until ready.
Meanwhile, prepare all the herbs and vegetables. Mix the nuoc cham and set aside.
Remove the sirloin from the lime mixture and drain the excess juice. Combine with the herbs, chilli, lemongrass, red onion and bean sprouts.
Transfer onto a serving plate and garnish with the fried garlic, crispy fried Asian shallots, peanuts and kaffir lime leaves.
Dress with nuoc cham and a squeeze of lime juice.