Pat chicken pieces dry with kitchen paper.
In a large shallow bowl, combine plain flour, cornflour, salt, black pepper, white pepper, paprika, garlic powder, onion powder, dried thyme and cayenne pepper; whisk to mix.
In a second shallow bowl, whisk eggs and full-fat milk together.
Dip each chicken piece into the egg mixture, let excess drip off, then press into seasoned flour to coat fully.
Return coated chicken to egg mixture briefly, then coat a second time in flour, pressing to adhere; place on a wire rack.
Heat vegetable oil in a deep heavy-bottomed pan or fryer to 170°C.
Carefully lower 3–4 pieces of chicken into hot oil without overcrowding and fry for 8–10 minutes per side, turning occasionally, until golden and internal temperature reaches 74°C.
Transfer fried chicken to a wire rack over a baking tray to drain excess oil.
Repeat frying with remaining chicken pieces.
Serve hot with chips, coleslaw or a green salad.