1. Preheat oven to 425F.
2. Line a baking tray with parchment or use a cast-iron Dutch oven and build a bed with the lemongrass, ginger and onion for the fish to sit on.
3. Combine curry paste, coconut milk, lime leaf, garlic, sugar and fish sauce in a frying pan. Heat over medium heat. Cook, stirring, 7–8 minutes or until thickened and aromatic. Set aside to cool.
4. Place the fish on prepared tray. Use a sharp knife to score 3 times on the thickest part of fish on both sides. Spread the curry paste mixture over both sides of fish and into fish cavity. Cover and place in the fridge for 30 minutes to marinate.
5. Combine the cilantro, basil, fried shallot and chiles in a bowl. Set aside.
6. Bake fish 20–25 minutes or until just cooked through. (Fish should flake easily with a fork.) Set aside for 5 minutes to rest.
7. Transfer the fish to a serving platter, spoon over any curry sauce from the tray and sprinkle with the herb-shallot mixture. Serve with lime wedges and rice.