In a mixing bowl, combine the chicken mince with half of the minced lemongrass, crushed garlic, fish sauce, and dark soy sauce. Mix well and let it sit for 30 minutes.

Wash the lettuce leaves under cold water and dry them thoroughly.

Heat 1-2 tablespoons of vegetable oil in a frying pan over medium-high heat until it shimmers.

Add the remaining minced lemongrass and crushed garlic to the pan and sauté for 1-2 minutes until fragrant.

Add the marinated chicken mixture into the pan and stir-fry for 5-7 minutes until cooked through.

Optional: Add a cornstarch slurry to thicken the filling, stirring until the desired consistency is reached.

Scoop the savory chicken filling into each lettuce leaf and top with grated peanuts and fresh coriander.