Cast Iron Blackened Salmon On the Grill: Easy 5-Step Recipe

by Jim Casey
photo by Jim Casey

Blackening salmon (or almost any fish) can be prepared indoors on your stovetop, but it’s a smoky affair best taken outdoors. The cooking technique involves heating a piece of cast iron, coating the fish in a spicy dry rub, and then quickly cooking at high temperature in butter or oil until a delicious, dark crust forms (hence the term blackening). As a result, there’s plenty of smoke. Emphasis on plenty.

If your gas grill has an external burner, that’s the go-to spot for blackening fish. Otherwise, a charcoal grill or gas grill works admirably. And, best of all, the inside of your house won’t smell like smoke for days. Of course, if you’re looking for more backyard grilling recipes from Outsider, check out our Best Damn Brisket, Spicy Spatchcock Chicken, Beef Short Ribs, Classic Cornbread, Reverse-Seared Pork Chops, or Skillet S’mores.

Blackened Salmon Ingredients

  • 1 pound salmon filet (wild-caught sockeye salmon)
  • 2 tbsp. blackening seasoning
  • 2 tbsp. butter
  • 2 tbsp. olive oil
Four simple ingredients: sockeye salmon, blackening seasoning, butter, and olive oil.

You can blacken almost any fish, but salmon, red fish, trout, grouper, pompano, and snapper are some of my favorites. In fact, blackening fish (red fish) was popularized by Cajun chef extraordinaire Paul Prudhomme (his Louisiana Kitchen cookbook is a must-own).

Today, we’re using a 1-pound filet of sockeye salmon—with the skin—that is about 1-inch thick. Buy (or trim) a filet that is equal in thickness throughout. This ensures the fish will cook evenly. Otherwise, you’ll end up with extra-crispy pieces (which isn’t a bad thing in my book).

Prep Work

Coat the flesh-side of the fish with the blackening seasoning, which consists of various crushed spices and herbs. You can make your own blackening seasoning, or there are plenty of great ones at the store, including Paul Prudhomme’s Magic or Tony Chachere’s).

Coat the flesh-side of the fish with blackening seasoning.

Blackened Salmon Directions

Fire up your gas or charcoal grill to 400-500 degrees. Or, if you are using the external burner on a gas grill, bring it up to high.

Place a cast iron skillet or griddle on the grill/burner for a couple of minutes. Having a pair of fireproof gloves around is a good idea, as well as a spatula with a long handle (the hot butter/oil can splatter).

Add 1 tbsp. butter and 1 tbsp. olive oil to the cast iron. Place fish on the cast iron, flesh-side down. Cook for about three to five minutes, depending on thickness. Add the rest of the butter and oil, and flip the fish. Cook for about three minutes to five minutes. We cooked our 1-inch-thick piece of salmon for three minutes on each side.

Remove the fish when it reaches your desired internal temperature. The FDA recommends 145 degrees. But many folks prefer medium-rare (around 125 degrees) if the fish is fresh.

Blackened salmon after cooking for six minutes (three minutes per side).

5-Step Blackened Salmon

  1. Coat the flesh-side of your fish with blackening seasoning.
  2. Fire up your gas or charcoal grill to 400-500 degrees.
  3. Place a cast iron skillet on the grill, bring to heat, add 1 tbsp. butter/oil.
  4. Place fish on skillet, flesh-side down, and cook for about three minutes.
  5. Add 1 tbsp. butter/oil, flip fish, and cook for an additional three minutes.
Enjoy your blackened salmon masterpiece.