Heat the oil in a large frying pan over high heat; partially cook the chicken in the hot oil in batches until completely browned. Transfer the browned chicken breasts to a plate and set aside
Reduce the heat under the frying pan to medium-high; add the onion, garlic, and ginger to the oil remaining in the frying pan and cook and stir until the onion turns translucent, about 8 minutes.
Stir the curry powder, cumin, turmeric, coriander, cayenne and 1 tablespoon of water into the onion mixture; allow to heat together for about 1 minute while stirring.
Mix the passata, yogurt, 1 tablespoon chopped coriander and 1 teaspoon salt into the mixture.
Return the chicken breast to the frying pan along with any juices on the plate. Pour 125ml water into the mixture; bring to the boil, turning the chicken to coat with the sauce. Sprinkle the garam masala and 1 tablespoon coriander over the chicken.
Cover the frying pan and simmer until the chicken breasts are no longer pink in the centre and the juices run clear, about 20 minutes.
Add a dollop of yogurt on top when serving if you can't handle the heat.