Whisk together the sesame oil, lemon juice, half the ginger and 1 tablespoon of the chopped mint in a shallow dish. Add the lamb and stir well, then cover and leave to marinate while you prepare the remaining ingredients.
Put the potatoes in a large pot and pour over enough boiling water to cover them. Bring back to a boil, half-cover the pan with a lid and simmer for 12 minutes or until almost tender when pierced with the tip of a sharp knife. Drain and leave until they are cool enough to handle. Cut across into slices slightly thicker than 5 mm, then cut the slices into thick french fries. Put them in a bowl, drizzle with 1 tablespoon of the canola oil and gently toss to coat. (This will stop the potatoes from sticking together when stir-fried.)
Heat 1 tablespoon of the remaining oil in a wok or large frying pan. When the oil is hot, add the lamb and stir-fry over a high heat for 1 minute or until just browned, but still fairly rare. Quickly remove and set aside.
Add the remaining oil to the wok and, when hot, add the sliced zucchini. Stir-fry for 1 minute, then add the french fries. Cook for 3-4 minutes, stirring all the time, until lightly browned, taking care not to break up the potatoes. Add the scallions and cook for 1 more minute, stirring.
Reduce the heat to medium and add the peas, soy sauce, stock, honey and remaining ginger. Return the lamb with any juices. Stir-fry for 2-3 minutes or until the liquid is bubbling and everything is tender and hot. Season to taste, scatter the remaining chopped mint over the top, then serve.
Variations: For a pork and pear stir-fry, use 350 grams lean pork. Instead of zucchini, quarter and slice 2 firm but ripe pears, preferably red-skinned; add them after the potatoes, at the same time as the scallions. For a vegetarian stir-fry, replace the lamb with 350 grams firm tofu (preferably smoked), cut into bite-sized cubes. Marinate the tofu in a mixture of 2 teaspoons sesame oil, 1 tablespoon salt-reduced soy sauce, 1 tablespoon mirin or sherry, 1 crushed garlic clove and 1 tablespoon finely chopped fresh ginger.
Cook's tip: If time permits, marinate the lamb for 2-3 hours to intensify the flavour.
Each serving: 28 g protein, 22 g fat of which 4.5 g saturates, 32 g carbohydrate, 7.5 g fibre, 451 Calories