The Cajun Secret to the Crispiest Cast-Iron Salmon
With a Louisiana-born Mom, and a Texas-bred Dad, the craving for Cajun and creole is a regular occurrence. So when I want to taste the flavors of home with minimal effort, it’s this Blackened Salmon recipe that I turn to.
The fact that something THIS flavorful comes together in under 15 minutes with just a cast-iron skillet and a homemade spice blend? I still don’t fully understand it. But I’m not questioning it.
I make this for Justin and me at least twice a month, and I promise… once you try it, you’ll understand why.
What Is Blackened Salmon?
If you’ve ever wondered what “blackened” actually means, it’s a Cajun cooking technique made famous by Chef Paul Prudhomme in the 1980s. The idea is simple: coat your protein in a bold spice blend, then cook it in a ripping-hot cast-iron skillet with butter until the spices form a dark, crispy, almost charred-looking crust on the outside.
The spices don’t actually burn. They toast and caramelize against the heat of the cast iron, creating this incredible smoky crust while the inside stays tender and flaky. The secret? A well-seasoned cast-iron skillet and high heat. (That’s it. No fancy restaurant equipment required.)
Ingredients
Salmon filets – Fresh, skin-on Atlantic or sockeye salmon works best here. You’ll want about 4-ounce portions so they cook evenly. (I grab mine from the seafood counter at HEB.)
Cajun seasoning – We’re using a homemade Cajun seasoning blend, which is SO much better than the store-bought stuff. You can control the heat level and skip the excess sodium.
Butter – Unsalted butter gives you that rich, golden sear and adds flavor without burning as quickly as olive oil would at this heat. This is a MUST for that traditional Cajun flavor.
Lemon – A squeeze of fresh lemon juice at the end brightens everything up and cuts through the richness of the butter and spices. Some would say optional, but I say it’s key.
Fresh parsley – For garnish. Totally optional, but it makes the plate look SO pretty.
Mix the spice blend.
Combine all the Cajun seasoning ingredients in a small bowl and give it a good stir so everything is evenly mixed. This takes about 30 seconds and makes enough for all five filets. If you already have homemade Cajun seasoning prepped, even better.
Prep the salmon.
Use a sharp knife to portion your salmon into five 4-ounce filets (if it isn’t already cut). Pat each filet completely dry with paper towels, then sprinkle the Cajun seasoning generously over both sides. Use your fingers to gently press the seasoning into the fish so it sticks.
Don’t be shy with the seasoning. A generous coating is what creates that signature blackened crust. The spices mellow slightly during cooking, so what looks like a lot will be just right.
Sear in the cast-iron skillet.
Heat your cast-iron skillet over medium-high heat until it’s VERY hot (about 2-3 minutes). Add the butter and let it melt and start to foam. Place the salmon filets skin-side up in the skillet. You’ll hear a serious sizzle. That’s exactly what you want.
Don’t move the fish once it hits the pan. Let it cook undisturbed for 3-4 minutes. That’s how you get the deep, dark, crispy crust. You’ll see smoke, and that’s totally normal with blackened cooking. Turn on your vent fan!
Flip and finish cooking.
After 3-4 minutes, use a thin spatula to carefully flip each filet. Cook for another 2-3 minutes on the second side until the salmon reaches an internal temperature of 145°F. The filets should feel firm but still have a little give when you press the top.
Rest and serve.
Remove the salmon from the skillet and let it rest for about 1 minute. Squeeze fresh lemon juice over the top and garnish with chopped parsley. When eating, simply peel the skin off the bottom (leaving the crispy, flavorful fat layer underneath). SO good.
Oops! What Did I Do Wrong?
My salmon doesn’t have a dark, crispy crust.
Your skillet probably wasn’t hot enough. Cast iron needs a good 2-3 minutes over medium-high heat before you add the butter and fish. Also make sure you patted the salmon completely dry before seasoning.
The spices taste burned, not smoky.
The heat was likely too high or the filets were in the pan too long. Medium-high (not high) is the sweet spot. The spices should char slightly and smell incredible, not taste bitter.
My salmon is dry inside.
It was overcooked. Pull the salmon off the heat at 140-145°F since it will continue cooking from residual heat. For salmon, slightly translucent in the very center is actually perfect.
The salmon stuck to my pan.
Two common causes: the pan wasn’t hot enough, or it wasn’t well-seasoned. Make sure the butter is fully melted and foaming before adding the fish. And let it cook undisturbed so the crust can form and release naturally.
Storage & Reheating
Store leftover blackened salmon in an airtight container in the refrigerator for up to 3 days.
To reheat, place filets in a skillet over medium-low heat for 2-3 minutes per side. (The microwave works, but you’ll lose some of that crispy crust.)
Leftover salmon is also amazing cold, flaked over a salad or tucked into fish tacos.
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Blackened Salmon
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Ingredients
- 1 lb. salmon
- 2 Tbsp. salted butter
- 1 lemon cut into wedges
Cajun Seasoning (Blackened Seasoning)
- 1 tsp. paprika
- 1 tsp. garlic powder
- 1 tsp. onion powder
- 1 tsp. black pepper
- ½ tsp. dried oregano
- ½ tsp. dried thyme
- ¼ tsp. cayenne pepper plus more to taste
- ¾ tsp. salt plus more to taste
Instructions
- Mix the spice blend. Combine the paprika, garlic powder, onion powder, black pepper, oregano, thyme, cayenne pepper, and salt in a small bowl. Stir until evenly blended.1 tsp. paprika, 1 tsp. garlic powder, 1 tsp. onion powder, 1 tsp. black pepper, ½ tsp. dried oregano, ½ tsp. dried thyme, ¼ tsp. cayenne pepper, ¾ tsp. salt
- Prep the salmon. Cut the salmon into five 4-ounce filets, leaving the skin on. Pat each filet completely dry with paper towels. Sprinkle the Cajun seasoning generously over both sides of each filet and press it gently into the fish.1 lb. salmon
- Sear in the cast-iron skillet. Heat a cast-iron skillet over medium-high heat for 2-3 minutes. Add the butter and let it melt until foaming. Place salmon filets skin-side up in the skillet. Cook undisturbed for 3-4 minutes until a dark, crispy crust forms.
- Flip and finish. Carefully flip each filet and cook for another 2-3 minutes on the second side until the internal temperature reaches 145°F.
- Serve. Remove from the skillet and let rest for 1 minute. Squeeze fresh lemon juice over the top and garnish with fresh parsley.2 Tbsp. salted butter
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Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
What to Serve with Blackened Salmon
This salmon is already loaded with bold Cajun spices, so keep your sides simple and fresh. Here are some of my favorites:
More Easy Salmon Recipes
Enjoy more of this delicious fish with these simple meals:
