Preheat the oven to 400°F.
Mix the turmeric and ground coriander together in a small bowl. Set aside.
Place the cauliflower florets, 1 tablespoon of melted coconut oil and half of the spice mix into a bowl and toss to combine. Transfer the cauliflower mixed with the spices onto a baking tray covered in parchment paper, season with a little salt and roast in the oven for 15 minutes, until golden. Set aside.
Rub the remaining turmeric spice into the flesh side of the snapper filets, then squeeze the juice of one lime over it. Leave to marinate for 10 minutes, cover and place in the refrigerator.
Meanwhile, heat the remaining coconut oil in a large frying pan over medium heat. Add the onion and sauté gently for five minutes until softened and translucent. Add the ginger and garlic and sauté for 30 seconds, then add the cardamom pods, cinnamon stick, chili flakes, a pinch of freshly cracked pepper and curry leaves, and cook for another minute.
Add the roasted cauliflower, okra, coconut milk and fish stock. Mix to combine, then place the fish flesh side down and gently simmer for eight to 10 minutes until the fish is nearly cooked through. When the fish is almost cooked, add the spinach leaves and gently mix them through.
To finish, season with the fish sauce, squeeze over the remaining lime juice, and garnish with fresh coriander.