Season the cod with salt, drizzle lightly with oil and place in a 30 x 23cm high-sided baking tray or an ovenproof pan of similar size. Toss to coat and set aside while you make the sauce.
Blitz the cherry tomatoes, coconut milk, sambal, onion, tomato purée, salt and sugar in a blender until smooth. Pour the sauce over the fish, turning the fillets to coat. Leave to marinate for 30 minutes at room temperature. Meanwhile, heat your oven grill to 250°C. Place the tray under the grill and cook for 20 to 25 minutes, or until the sauce is thickened and bubbling vigorously and everything is charred in places on top.
Finish with the coriander and a drizzle of chilli oil if you like, then serve straight away with steamed rice and greens.
