Add the gurnard fillets and prawns and cook for 2 minutes, then add the mussels and cook for a further 2–3 minutes until the mussels have opened (discard any mussels that do not open).
Remove from the fridge 20 minutes before cooking. You can tuck a few steamed spears of asparagus in the gurnard fillets along with the spinach. Instead of the parmesan use a grated tasty cheddar ...
Cooking fish fillets like this on the BBQ is super simple and fun to do. If you don’t have blue cod, you can use the likes of snapper, terakihi or gurnard.