For the Barramundi, remove fillets from barramundi and cut each in half. Place onto kitchen paper, skin side down to dry skin. Set aside in fridge.
For the Corn Purée, rub corn with 1 tablespoon of the butter, season with salt and pepper and wrap in foil. Place in pre-heated oven and cook until tender, about 20-25 minutes.
Remove corn from foil and slice off kernels. Place corn kernels into a small saucepan along with the remaining tablespoon of butter, salt and pepper to taste and cook for 2 minutes. Reserve 2 tablespoons of the cooked corn kernels for garnish.
Transfer the remainder of the corn kernels and any cooking liquid to blender and blitz until smooth. Pass through a fine sieve and set aside until needed.
Heat the oil in a small frypan over medium heat and cook the reserved corn kernels until golden. Drain on kitchen paper and set aside until needed to garnish.
For the Beetroot, combine sugar, water, vinegar and peppercorns in a small saucepan and bring to the boil.
Trim beetroots and, when vinegar mixture is boiling, add the beetroots to the saucepan. Simmer for 10 minutes or until tender.
Remove beetroots for the vinegar mixture and allow to cool. When beetroots are cool enough to handle, use a small paring knife to peel. Use a mandolin to slice one beetroot into thin slices about 1mm. Cut the remaining beets into 8ths. Set the beetroots aside until needed.
For the Coriander Oil, combine coriander leaves, grape seed oil, lime juice and zest, salt and pepper to taste and blitz in a food processor until smooth. Pass through a fine sieve, adjust seasoning if required and set aside.
To finish the Barramundi, rub skin with oil and season well. Place a large frypan over high heat. Add barramundi to pan, skin side down and press with a metal spatula until skin sets, about 30 seconds. Continue to cook for 4 minutes skin side down, until fish is approximately 2/3 cooked.
Transfer the fish to the pre-heated oven and cook for 3-4 minutes, or until cooked through. Remove pan from oven and flip fillets and return to oven for 1 minute. Place fish onto kitchen paper to drain.
To serve, season each barramundi fillet with salt and pepper and a squeeze of lime juice. Place one fillet of barramundi on each plate, skin side up. Add some corn puree, beetroot slices and pieces each plate. Garnish with coriander leaves and fried corn kernels. Drizzle coriander oil around the plate.