Mix all ingredients for the marinade in a large bowl.
Add the diced chicken and mix with the marinade so that each piece gets coated well.
Cover bowl with a clingfilm and set aside in the fridge for at least 30minutes.
In the meantime, prep your vegetables, toast both the cashew nuts and sesame seeds and keep aside.
Mix the ingredients for the sauce and keep aside
Heat oil in a wok on medium high. Add the chicken one by one and stir fry till brown on all sides (6-7mins). Do not crowd the chicken pieces or add any remaining marinade into the pan.
Add the mushrooms and sliced white part of the spring onions and chopped garlic, stir fry for 4mins.
Now add the peppers, stir fry for 3mins.
Tip in the prepared sauce and stir fry till everything is coated well and the sauce thickens(5-6mins).
Add the toasted cashews, toss well, and remove from heat.
Sprinkle with the sliced green spring onions and toasted sesame seeds before serving.
Serve with boiled jasmine or basmati rice.