1 cucumber, peeled, seeds removed, grated and drained
1 tbsp freshly chopped mint
Handful fresh mint or coriander leaves (optional)
Preheat the oven to 220°C/fan 200°C/gas mark 7.
Mix the tikka marinade ingredients together, rub over the gurnard and marinate for no more than 30 minutes
Prepare the vegetables: mix the red onion, garlic and ginger together. Pour the oil into the bottom of a large roasting tin and arrange the sweet potato across the base. Spoon over the onion mixture and season well with salt and pepper. Roast in the oven for 15 minutes or until the potatoes are soft.
Remove the sweet potato from the oven. Arrange the marinated gurnard on top of the sweet potato and return to the oven to roast for 10-12 minutes or until the gurnard is cooked. The fillet will pull away from the tail a little and will turn white.
Meanwhile, make the raita: mix the yoghurt with the cucumber and mint. Season with salt and pepper.
When the fish is cooked, transfer to plates, scatter over the herbs (if using) and serve with the warm naan bread, green beans and raita.