Mix all the ingredients for the marinade in a bowl.
Add chicken pieces and mix well.
Cover and keep aside for 30 minutes.
Heat oil for frying in a pan.
Once the oil is hot, add chicken pieces and fry on medium heat until slightly browned.
Fry the chicken in 2-3 batches.
Take out the fried chicken pieces on a tissue lined plate.
Now heat the oil once again until it is very hot.
Fry the chicken second time on high heat until they are nicely browned.
Drain on a tissue lined plate and keep aside.
For the sauce, heat vegetable oil in pan.
Add ginger and garlic and fry for a minute.
Now add onion, green chilli and capsicum and fry for a minute.
Next up add soy sauce, vinegar, tomato ketchup, red chilli paste, salt and black pepper powder and cook for a few seconds.
Finally add the fried chicken and quickly toss in the sauce.
Garnish with spring onion greens.
Double frying the chicken makes it very crispy and crunchy, so do not miss this step.You can adjust the amount of green chillies and red chilli paste according to your taste preference.Add a slurry of cornflour and water to make chilli chicken gravy.