Seared Miso Butter Halibut in One Skillet, Ready in Under 30 Minutes

Halibut is one of the few white fish firm enough to hold up to a hot cast iron pan. Brown butter, sweet miso and fresh ginger turn a simple fillet into a glossy, savory dinner with mushrooms and crisp green onions, all cooked in one skillet and served straight from the pan.

This seared miso butter halibut starts with thick, skin-on halibut fillets, fresh shiitake mushrooms and baby bok choy. The fish is seasoned simply with salt and black pepper, then cooked in foaming butter that carries grated ginger and a spoonful of miso butter. The result is fish with a golden, crisp skin and a moist, flaky center, set in a rich, savory sauce.

Everything happens in one cast iron skillet, so there are few dishes to wash and the sauce stays hot from the pan to the table. The method is quick, and each step gives clear signs of doneness. Read through the steps once before you start, because the halibut moves from raw to cooked in a few minutes.

Ingredients

Why this recipe works

Searing the halibut skin-side down in foaming butter does two jobs at once. The hot fat crisps the skin and gives the flesh a golden edge, while the continuous basting with a spoon pushes heat gently across the top of the fillet. Halibut is lean, so the butter also protects it from drying out. The fish cooks through in the time it takes to brown one side and finish the other, which keeps the flesh moist and flaky rather than tough.

Adding the mushrooms and ginger to the butter before the fish goes in lets their flavors release into the fat and form the sauce. Shiitake give up their juices and brown at the edges of the skillet, while the ginger softens and perfumes the butter.

The miso melts into the fat and adds salt and depth, so the sauce tastes finished without any extra ingredients. Because everything shares one pan, the fish and sauce are seasoned together and the fond on the bottom of the skillet is carried into the final dish.

Notes and substitutions

Halibut is the star of this dish, so choose firm, bright white fillets with a clean smell and skin still attached. Ask the fishmonger to portion them to an even thickness, which lets the whole piece cook at the same speed.

If halibut is not available, cod, sea bass or skin-on salmon work well, but thin fillets need less time in the pan. Keep the fish refrigerated until you are ready to cook it, and take it out no more than 30 minutes before it goes into the skillet.

A 12-inch cast iron skillet is the right size for two fillets with mushrooms and sauce, because it holds heat evenly and gives a strong sear. Use a box grater for the ginger so the fine pulp melts into the butter.

A thin, sturdy pair of tongs helps you flip the fish without tearing the skin, and a large spoon is needed for basting. Miso butter is simply white miso blended with softened butter; make a small batch and keep it in the refrigerator for quick sauces.

• Halibut: Cod, sea bass or skin-on salmon fillets of similar thickness; adjust the sear time until the flesh flakes.
• Shiitake mushrooms: Cremini or oyster mushrooms, sliced to a similar thickness.
• Baby bok choy: Baby spinach stirred in at the end, or thinly sliced napa cabbage.
• White miso: Yellow miso for a deeper, saltier flavor; use slightly less.

Equipment

• 12-inch cast iron skillet
• Wooden cutting board
• Chef's knife
• Box grater
• Tongs
• Large spoon for basting