Anyway, Neua Yang Nam Tok is litteraly called Waterfall Beef in Thai, and it's quite easy to do...and really really one of my fav' dish in Thailand.
Here's the recipe from my daily website i check as often as Brainfeeder one
A Must Have in Thai Cooking
You need a 1 pound steak, cut fairly thick.
1 tablespoon fish sauce
1 teaspoon tamarind concentrate mixed with 3 teaspoons water
1 tablespoon lime juice
1 tablespoon chopped Thai chile peppers
Mix the marinade, coat the steak with it and marinade it for at least 3 hours.
The steak is then barbequed, broiled or grilled until on the rare side of medium rare, cut into half inch thick strips and the strips cut into bite sized pieces. The meat can be kept cool until just before you want to eat.
1/3 cup fish sauce
1/3 cup lime juice
2-3 tablespoons chopped shallots
2-3 tablespoons chopped coriander/cilantro (including the roots if possible)
2-3 tablespoons chopped mint leaves
2 tablespoons khao koor (see below)
1 tablespoon freshly roasted/fried sesame seeds
1-3 teaspoons freshly ground dried red chilis.
Khao Koor: get a medium sized wok fairly hot, and add a couple of tablespoons of uncooked jasmine rice. Keep in movement until the rice starts to turn golden brown. Remove from the heat and allow to cool. Grind to a fairly coarse powder in a spice mill, or a mortar and pestle, or a pepper mill or a good clean coffee grinder (all of these work well but keep in mind that a coffee grinder tends to grind too fine--the powder should retain some "texture") We also offer ready-made Khao Koor in premium quality Hand Brand.
In a wok bring a little oil to medium high heat and add the strips of beef, immediately followed by all the remaining ingredients. Stir fry until heated through (about a minute).
Serve with Thai sticky rice, or as part of a meal with pad Thai and a soup such as tom yum koong (hot and sour shrimp soup).