Prepare the stir-fry sauce in a bowl using the ingredients written under 'stir-fry sauce'.
Marinate the chicken pieces with sweet soy sauce, salt and white pepper powder for 10 minutes.
Meanwhile prep the veggies.
Take a large wok, add oil and let it heat up on a medium-high flame. Add the chopped garlic, sliced ginger and sliced onion, sauté and cook for 2 minutes.
Add the chicken pieces. Spread the chicken pieces so that each piece is evenly browning. Cook for 3 minutes, then flip and let it cook for another 2 minutes.
Now add the sliced mushrooms and cut spring onions. Mix well and cook for 2 minutes.
Finally add in the stir-fry sauce and mix. Let the chicken pieces absorb all the sauces. Switch off the flame. Garnish with some more spring onion greens.
Enjoy with steaming hot rice or noodles!