Mix the beef, lemon grass, chilies, sugar,
ginger, cinnamon, curry powder, Nuoc Mam sauce, salt and black pepper
and leave to stand for 1 hour.
Heat 4 tablespoons oil in the wok over a
high heat. Add the beef and marinade and stir quickly to sear.
This should not take much more than 2
minutes. Remove the meat to a bowl and set aside.
Add a little more oil, and when hot, add
the onion and garlic and stir fry until fragrant.
Add the tomato puree and stir for 2
minutes.
Add the beef, star anise, a little salt
and the water. Bring the mixture to the boil, reduce the heat to low,
cover the wok and simmer until the beef is tender about 1 1/2 hours.
Add the carrots and simmer for 10 minutes.
Add the potatoes and simmer for a further
10 minutes. Finally, add the daikon and cook for another 10 minutes.