Cut chicken into bite-sized pieces. Make up the marinade, work through the chicken and finish by dusting with a little cornflour and set aside.
Wedge-cut the Capsicum and chop the spring onion, mainly the white parts, into 4cm lengths. Set aside.
Wash the Nashi, core, cut in half, then cut each half into 8 wedge shape slices and set aside.
Make up the sauce and the thickening in separate mixing bowls and set aside.
To prepare and condition the Walnuts: first simmer in lightly salted boiling water for 6-7 minutes. Quench immediately under cold running water, drain and spread out to dry on paper towels. Then, adding sufficient oil to your wok, carefully deep-fry the Walnuts until golden brown. Drain and set aside.
Pre-heat wok, add 2 tablespoons of oil and when slightly smoking add the Ginger followed by the Chicken. Stir-fry over heat for 1-2 minutes. When you see the colour change, add a sprinkle of Salt and the Hoi Sin sauce and sauté briefly before removing contents to a plate.
Wipe out your wok, add 2 tablespoons of oil and, on moderate heat, just as the oil begins to smoke, add a little Salt followed by the Capsicum, Spring Onion, Nashi and Mushrooms. Quickly stir-fry for 30 seconds before returning the Chicken, combining well.
Add the Chicken Stock and the sauce and toss through. Finally, make a space in the centre bottom of the wok and add the thickening stirring quickly until it coats your spatula then through the contents until all ingredients are lightly coated with a velvet-like finish. Add the Walnuts, combining well and transfer contents to a serving dish. Serve immediately.