In a large bowl, combine the garlic, onion, lemongrass, chilli, pepper, fish sauce and honey and marinate the beef in this mixture for 30 minutes.
Put the rice noodles in a saucepan or heatproof bowl, pour boiling watre over them, cover and leave for 5 minutes, then drain. Divide the noodles between individial deep bowls, then add the beansprouts, Chinese greens, cucumber and mint.
Heat a frying pan or griddle over a high heat and spray lightly with oil, if necessary. Sear the beef for 30 seconds each side then add to the bowls. Pour a little stock into each bowl and then sprinkle with the nuts and the seeds.