Prep the lemongrass, serrano and scallions.
Slice the shallots then rinse them under cold water. Add the shallots, serrano, scallions, lemongrass, lime juice, fish sauce and honey to the beef. Stir in the cilantro and mint.
Top the beef larb with the toasted peanuts and onion flakes, then serve in cabbage leaves with cooked rice.