To make the sauce peel and chop the onion and garlic. Grate the ginger root and seed and chop the chillies.
Add the oil to the pan.
Add the onion and fry until the onion starts to soften
Add the ginger, garlic and chillies and fry on a low heat until the onion is soft.
Add the spices and cook gently for a few minutes. Remove from heat.
Add the water to a food processor then add the onion mixture.
Blend until smooth and then add the flour and blend.
Place the mixture back in the pan and simmer over a low heat until it darkens
Add the chicken stock and simmer until reduced into a thick sauce.
Chop the chicken into pieces and coat in cornflour.
Heat the oil in a large frying pan and cook the chicken until it is white
Add the onion and peas and cook for a couple of minutes.
Add the sauce and heat until hot