Directions

1. Preheat the oven to a low setting. Trim, rinse, and drain the watercress and set aside.
2. Trim any fat and tissue off the pork, then cut it into ½ in. (1 cm) slices and place in a bowl. Stir in the ginger and set aside.
3. Scrub the potatoes, cut them into ½ in. (1 cm) thick slices and put them into a saucepan. Cover with cold water, add salt, and bring to the boil. Then cover and boil gently for 10-12 minutes, or until tender.
4. Meanwhile, fry the sesame seeds in a dry frying pan, shaking them over a moderate heat until lightly toasted, then leave to cool.
5. In a small bowl, lightly beat the egg with salt and pepper, and stir in the sesame seeds. Heat the sesame oil and 1 teaspoon of vegetable oil in the frying pan. Add the egg and swirl it over the base to make a thin omelette. Turn it out onto a plate, roll it up, and slice it thinly.
6. In a small jug or bowl, blend the cornstarch with 2½ tablespoons of cold water, then stir in the sherry and soy sauce.
7. Heat the remaining oil in the frying pan over a 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.
8. Pour the cornstarch mixture into the pan and stir over a moderate heat until it boils and thickens. Return the pork to the pan with any juices and heat through.
9. Drain the potatoes and arrange on two plates. Place the watercress and pork on top and pour the sauce over; garnish with omelette ribbons.