Combine egg and soy sauce in a bowl. Add chicken pieces and stir to coat. Working in batches, toss chicken through the cornflour, shaking off any excess.
Heat oil in a wok or saucepan. Fry the chicken in batches for 4-5 min until lightly golden and cooked through. Drain on paper towel. Set aside and keep warm.
Pour Lemon Chicken Sauce in a fry pan over medium-low heat.
Add chicken, stir gently to coat, cook for 2 minutes or until heated through.
Garnish with sesame seeds and spring onions. Serve with steamed rice.