Make deep slashes all over the pork with a sharp knife and place in a shallow glass or ceramic dish. Mix together all the remaining ingredients and spread all over the pork, rubbing it into the slashes. Cover and leave to marinate in the refrigerator for 3–4 hours, or overnight if time permits.
Place a roasting rack or wire rack over a roasting tin. Pour hot water into the tin to come halfway up the sides. Remove the pork from marinade, reserving the marinade, and lay on the rack. Place in a preheated oven, 200°C (400°F), Gas Mark 6, and roast for 20 minutes.
Turn the pork over and brush well with some of the marinade. Reduce the oven temperature to 180°C (350°F), Gas Mark 4, and roast for a further 20 minutes. Remove from the oven, cover with foil and leave to rest for 10–15 minutes.
Meanwhile, place the remaining marinade in a small saucepan and bring to the boil.
Slice the pork thinly and serve with the extra marinade, together with egg noodles and steamed Asian greens.