Place the parsnips and celery root in a large pot and cover with cold water. Bring up to a boil and simmer for about 20 minutes or until fork tender.

Add blood orange juice, sugar, and a generous pinch of salt to a small saucepan. Place over medium-high heat and simmer until reduced by half, about 10 minutes. Remove from heat.

Drain celery root and parsnips completely, then transfer to a bowl. Add melted butter, half and half, salt and white pepper. Use an immersion blender to puree until very smooth. Taste and adjust seasoning as needed, then cover and set aside in a warm place until ready to serve.

In a small bowl, combine the shallot, apple, and parsley. Drizzle with 1 tablespoon olive oil, lemon juice, and season with salt and pepper. Gently toss to coat.

Heat 2 tablespoons olive oil in a large skillet (well-seasoned cast iron works best) over medium-high heat. Use paper towels to pat the barramundi fillets very dry, being sure to remove as much moisture as possible. Season both sides with salt and pepper. When the oil is shimmering and almost smoking, gently place two fillets in the pan, (skin side down if using skin-on fillets). Allow to cook in the hot oil without moving for about 3 minutes.

The fish will be ready to flip when it easily releases from the pan. If it sticks, it’s not ready. Lower the heat and give it another minute. Use a fish spatula to gently flip the fillets and cook on the other side for another 2-3 minutes, depending on thickness. Transfer to a plate and repeat with remaining fillets.

Whisk the remaining tablespoon of butter into the blood orange reduction over low heat, then taste for seasoning and adjust as needed.

To serve, place a generous dollop of celery root parsnip puree on each plate, then top with barramundi fillets. Drizzle the blood orange sauce around the perimeter and garnish a handful of apple parsley salad on top. Serve immediately.