Preheat the oven to low. Trim the watercress and put aside.
Trim any fat and tissue from the pork, then cut into 1cm slices and place in a bowl. Stir in the ginger and put aside.
Scrub the potatoes, cut into 1cm slices and put into a saucepan. Cover with cold water, add a little salt and bring to the boil. Then cover and cook for 10–12 minutes, or until tender.
Meanwhile, dry-fry the sesame seeds in a frying pan, shaking over moderate heat until lightly toasted, then leave to cool.
Lightly beat the egg in a small bowl with salt and pepper, then stir in the sesame seeds. Heat the sesame oil and 1 teaspoon vegetable oil in the frying pan. Add the egg and swirl over the base to make a thin omelette. Turn out onto a plate, roll up and slice thinly.
Blend the cornflour in a small bowl with 2 tablespoons cold water; stir in the sherry and soy sauce.
Heat the remaining vegetable oil in the pan over high heat and fry the pork slices for 1–2 minutes on each side until golden brown, then transfer to a plate and keep warm.
Pour the cornflour mixture into the pan and stir over moderate heat until it boils and thickens. Return the pork to the pan with any juices and heat through.
Drain the potatoes and arrange on two plates. Place the watercress and pork slices on top and pour over the sauce; garnish with the omelette ribbons and serve.
NUTRIENTS PER SERVING:
good source of vitamins A, B group and C, and selenium and zinc.