Cook the steak, preferably over a charcoal barbecue (or simply fry in a frypan on a stove top), until the meat is medium rare. Let the meat rest.
Meanwhile, toast the uncooked glutinous rice in a dry frypan on the stove until the rice is well toasted, almost burnt. Let the rice cool then grind the rice in a clean coffee grinder until fine; or grind in a mortar and pestle until fine.
In a bowl make the dressing by mixing the lime juice, fish sauce, tamarind, salt and chilli flakes.
Slice the beef thinly into strips and place in the bowl along with the dressing. Toss lightly. Add the shallots, mint and rice powder. Mix everything well.
Give the salad a taste and adjust if it needs balancing. The salad should have a balanced spicy heat from the chilli flakes, sour from the lime, pungency from the fish sauce and saltiness from the salt.
Lay the lettuce out on a platter and place the meat mixture on top to serve.