Place the oil and the Knorr Chicken Stock Pot in a small frying pan and heat gently until the stock melts. Remove from heat and leave to cool for 5-10 minutes. Rub melted stock all over the chicken pieces, massaging well into the skin.
In a large bowl, mix the yoghurt with enough milk to thin it down to the consistency of cream. Add the thyme and garlic powder. Add the chicken to the bowl, making sure to cover it completely and mix well. Cover the bowl and place in the fridge for at least one hour but ideally overnight.
Preheat oven to 170°C.
Lay out a large baking tray and place a wire rack over another baking tray.
Mix the plain flour, corn flour and white pepper together in large bowl.
Using tongs, lift a piece of chicken from its marinade and roll into the flour. Pick it back up with tongs, give it a shake, and lay on the wire rack. Repeat until all chicken pieces are coated in flour.
Fill a large frying pan half with vegetable oil. Place over a medium heat, when the oil is hot place as many chicken pieces into the oil as as you can without overcrowding. Cook on both sides until the crust has turned golden, about 6-8 minutes.
Remove from pan using tongs and place on the baking tray. Put the tray in the oven and bake for 20-30 minutes until chicken is cooked, turning once after 15 minutes.