Preheat the oven to 180°C.
Mix tomato purée with 15ml of water in a bowl.
Incorporate the remaining sauce ingredients into the bowl in the order listed.
Season the chicken breasts on both sides with salt and pepper.
Heat 45ml of oil in a non-stick frying pan over high heat.
Add cinnamon, cardamom, and cloves to the hot oil.
Lightly brown the chicken breasts on both sides in the pan.
Transfer the chicken to a single layer in an ovenproof dish using a slotted spoon.
Fry onions, ginger, and green chillies in the remaining pan oil until golden-brown.
Spread the fried onion mixture evenly over the chicken.
Heat the remaining 15ml of oil in the pan and add mustard seeds until they pop.
Add garlic to the pan and stir until it begins to brown.
Pour the sauce into the pan until it heats and bubbles.
Pour the hot sauce over the chicken and bake uncovered for 25 minutes.
Serve immediately with basmati rice.