Heat a pan on medium high heat. Add oil and onions, sauté for a few minutes then add ginger and garlic and sauté until soft.
Stir in the curry powder and turmeric for 30 seconds then add stock, soy sauce, fish sauce and sugar and bring to a simmer for 5 minutes.
Stir in the cornflour mixture and bring back to a simmer, blend until smooth. Simmer for 2 more minutes, stir, cover and set aside.
Put the chicken in a mixing bowl with salt, pepper and cornflour and stir well. Put 75g plain flour on a plate ready to coat the chicken.
Add vegetable oil to a wok to a depth of 5-6cm and heat on high. While heating, mix the batter by whisking together self-raising flour, baking powder and cold water.
Dust half the chicken pieces in the flour. Once oil is hot, dip each chicken piece in batter and gently drop into the oil.
Fry for 5-6 minutes until golden brown, turning halfway through. Remove and set aside. Repeat with second batch of chicken.
Heat the sauce and serve with the chicken balls.
