Marinate the meat
Mix the tamarind paste with all the ingredients up to and including the coriander seeds. Brush the meat with one quarter of the marinade, cover and marinate in the fridge for approx. 12 hrs. Set aside the remaining marinade.
Brush the pak choi and asparagus with the oil, place on a grill tray.
Wipe the marinade off the meat and set aside, season the meat with salt. With the lid down, grill the meat over/on a low heat (approx. 160 °C for approx. 55 mins., turning occasionally, brush with the wiped-off marinade (core temperature should reach approx. 70 °C. Cover the meat and leave to rest for approx. 10 mins. Meanwhile, grill the vegetables over/on a medium heat for approx. 5 mins. on each side.
Place the rice vermicelli in a bowl, pour over boiling water and leave to stand for approx. 5 mins. Heat the reserved marinade in a pan, cook for approx. 5 mins. Drain the rice vermicelli, mix with the marinade, scatter the coriander over the top. Carve the meat and serve it with the vegetables and the rice vermicelli.