Add half the curry paste (see tip). Stir well to coat the chicken and onions in the paste. Fry for 1–2 minutes, or until fragrant. Add the potato, chillies, stock, coconut milk, tomatoes ...
Cut the chicken breasts in half ... and add the ginger with the remaining Thai curry paste and fry for a minute. Sprinkle in the flour and blend in the coconut milk with the fish sauce and sugar ...