General tips
Black cod is also called sablefish, butterfish, or gindara. Whatever the label, it's so naturally oily that it can take far higher temperatures than most fish without drying out. But the sweet spot is still 122°F - go higher and you cook out the fat that defines it.
Marinate in white miso for 24 h minimum. The classic Nobu black cod miso marinade needs a full day to penetrate the dense flesh. Half a day gives you surface flavor only. Three days starts to cure the fish - find the 24-hour middle.
Sous vide at 122°F for 45–60 min. The fish is so rich that this brief, gentle bath is enough to set the flesh while keeping the fat intact. Anything longer just risks the texture going pasty.
Broil the top, never the bottom. After the bath, pat the fish dry, brush with a bit of leftover miso marinade, and broil 4 inches under a hot element for 90 sec. The miso glazes and the surface caramelizes in seconds. The bath has already cooked the fish through.
Anti-tip: don't pair black cod with delicate sides. The fish is so rich and intense that subtle accompaniments get steamrolled. Serve with pickled ginger, sharp greens, or steamed rice with strong umami flavors. Don't waste it on plain white sauce.
Butter-Soft tips
Don't overcook - black cod is best medium-rare to medium
The high fat content prevents drying
Marinate overnight for deepest flavor