Heat oven to 200°C.
Heat the oil and temper the spices and allow to crackle. Add the onions, with a pinch of salt, and then the leeks. Add the garlic and cook through allowing the onions and leaks to sweat off and soften.
Scatter in the spinach and the chilli flakes and then pour in the cream.
Add the fish and herbs, simmer gently until fish is cooked through.
Remove from heat, season and place in casserole dish.
Heat the ghee in a frying pan and the add the potato, Sauté for 5 minutes until the potatoes begin to crisp then mix in the chives and the chilli flakes.
Top the fish with the sautéed potato and then place under the grill for 10 – 15 minutes until the potatoes are golden brown and crispy.
Bake in the oven for 15 minutes, until the top is golden brown.