Heavenly Halibut

Chef's notes

Halibut is done in the first broil when it registers 130 to 135 F internally and the flesh turns opaque and flakes with a fork -- pull it right at that point before adding the topping, as it will carry over another few degrees under the broiler. Mix the Parmesan topping first, before the fish even goes under the broiler, so it is ready to spread the moment the fillets come out and you lose no heat. The most common mistake is letting the topping brown too long -- watch it constantly for those final 2 minutes, as the high butter and cheese content can go from golden to burnt in under 30 seconds. No halibut available? Thick cod or mahi-mahi fillets of similar weight work well and broil in the same time window. The Parmesan topping can be made up to 24 hours ahead and stored covered in the refrigerator; bring it to room temperature for about 15 minutes before spreading so it layers evenly over the hot fish.