Thinly slice the partially cooked beef and pound lightly with a pestle to make it tender.
Heat the oil in a wok and fry the beef but don’t allow it to become too crispy.
Remove beef from the wok. Saute the blended lemongrass, garlic, chillis, and onions.
Cook till the oil separates. Add beef stock, sugar, salt, and soy sauce. Bring to a boil.
Add beef and reduce the heat. Allow to simmer and thicken.