Grill meat or fry medium in a wok in very little oil on both sides (about 3 minutes each side). Wrap in aluminum foil and let rest a little.
Mash the ingredients for the dressing in a mortar in this order: coriander root, salt, garlic, chillies, sugar, lime juice, fish sauce.
Mix the onions, spring onions, both kinds of coriander, chili pepper and rice semolina in a bowl. Cut the meat into thin slices and place in the bowl. Mix well with the dressing and then arrange on two plates.