Start by combining all the marinade ingredients in a bowl and mix well. Set aside.

Remove the skin of the fish, and add the marinade. Coat well and leave for 30 minutes-1 hour.

Preheat the oven/airfryer to 220. Line a baking dish with baking paper and place the fish on top. 

Cook for 10 minutes, or until caramelized nicely. Drop temperature to 160 and cook for an additional 4 minutes. Remove from the oven and rest for at least 5 minutes.

While resting, chop the choy sum and wash thoroughly. Sautee the choy sum on medium heat for 1 minute and add 2 tbsp of Lemon Myrtle & Yuzu Ponzu. Remove from the pan.

To serve, place choy sum on a serving dish, Lift the barramundi out of the dish, and slide on top of the choy sum. Add a slice of fresh or grilled lemon to squeeze over the top.