Brown Butter Poached Halibut with Barbecued Potatoes and Champagne Caviar Sauce

Place the scrubbed new potatoes into the large stockpot, cover with cold water by 3 cm, add 2g fine sea salt, and bring to a boil over high heat, cooking for 12 minutes until tender when pierced with the tip of a paring knife.

Drain the cooked potatoes using the spider strainer, spread them onto a tray to steam dry for 5 minutes, then crush each potato gently with the palm of your hand to crack the skin while keeping them intact.

Refill the large stockpot with unsalted water, bring to a rapid boil, add the trimmed samphire, and blanch for precisely 90 seconds.

Transfer the blanched samphire immediately into a mixing bowl filled with ice water to arrest cooking completely, leave for 2 minutes, then drain thoroughly.

Preheat your outdoor barbecue grill to 220°C (428°F) on high direct heat, brush the crushed potatoes with 20ml olive oil, season with 1g fine sea salt and 1g cracked black pepper, then grill for 8 minutes, turning once halfway through, until charred and crisp.

In a medium wide saucepan over medium heat at 160°C (320°F), melt the 400g unsalted butter, swirling frequently for 6 minutes until the milk solids turn hazelnut brown and release a fragrant nutty aroma, then add thyme and crushed garlic.

Lower the heat beneath the brown butter to maintain a steady liquid temperature between 65°C and 70°C (149°F and 158°F), using the digital probe thermometer to verify the reading.

In a small heavy saucepan, combine 150ml brut champagne and 40g minced shallot, place over medium-high heat at 100°C (212°F), and reduce for 5 minutes until approximately 30ml of syrupy liquid remains.

Pour 100ml fish stock and 120ml heavy cream into the champagne reduction, bring to a gentle simmer at 85°C (185°F), and cook for 4 minutes until the mixture coats the back of a spoon lightly.

Reduce the heat under the cream sauce to lowest setting (around 50°C / 122°F), then vigorously whisk in the 50g chilled cubed unsalted butter one piece at a time to form an emulsified, glossy velouté sauce.

Season the raw halibut fillets evenly with 3g fine sea salt, practice strict cross-contamination hygiene by washing hands and tools, then gently submerge the fillets into the 68°C (154°F) brown butter bath, poaching for 10 minutes until the digital probe inserted into the thickest center registers 63°C (145°F) and the opaque flesh flakes gently under light pressure.

In a small skillet or the stockpot, melt 15g unsalted butter over medium heat at 120°C (248°F), add the drained samphire, and toss for 1 minute until warmed through.

Remove the champagne sauce completely from the heat, stir in 5ml lemon juice, and gently fold in the 40g caviar using a spoon, taking care not to crush the delicate roe.

Arrange the warm barbecued potatoes and glossy samphire across 4 warmed serving plates, lift each halibut fillet from the brown butter using the fish spatula, drain excess butter briefly, position atop the samphire, and ladle the warm champagne caviar sauce generously over and around the fish before serving immediately.