Blackened Mahi Mahi

This Blackened Mahi Mahi Recipe is a nutrient-packed and tasty dinner-in-a-hurry. Use store-bought Cajun seasoning or make your own from pantry ingredients (spice recipe included!) No special equipment or skills involved. Just a flavorful fish dinner your whole family will love.

This blackened fish recipe has a prep time of 5 minutes and a cooking time of less than 10 minutes.

You probably already have butter in your fridge and a bottle of cajun seasoning blend in the spice drawer. If you need to make your own spice blend, keep scrolling for the perfect solution.

I have found the best way to get the perfect char on the blackened fish fillet while retaining the flaky texture of the cod is to use a cast iron skillet over medium-high heat. But if your only option is a non-stick skillet, you'll still get a tasty fish dinner.

If you want to add more easy mahi recipes to your weekly menu, check out my Pan Seared Mahi Mahi in Garlic Sauce, Blackened Mahi Tacos or Crispy Air Fryer Mahi Mahi.

What you'll need to make this recipe:

Before we get to the step by step directions, a few notes about the ingredients:

Fish: the recipe calls for Mahi Mahi, but this simple blackening method can be used on almost any fish, from Grouper Sandwiches to Halibut Fillets to Blackened Tuna Steaks.

Butter: the process of blackening fish depends on the milk solids in the butter to accelerate the "blackening" process. I always use salted butter, but use what you have. You can substitute oil for butter, if needed.

Full ingredient list and measurements included in the printable recipe card below.

Step by step instructions:

1. Prep fish

Melt butter and measure out blackening seasoning. If using ready-made seasoning, taste a bit of the spice mixture to determine if it needs a pinch more salt or sugar to balance the flavor.

Use paper towels to dry fish well, removing excess moisture. Brush melted butter over fillets, then sprinkle liberally with blackening seasoning.

2. Sear mahi fish

Preheat a cast iron skillet over medium high heat. When the pan is hot, gently add your mahi fillets, seasoning side down. Brush the second side with butter and lightly season with blackening spice.

Cook for 3 minutes, until the Mahi Mahi fillets are about 70% cooked through and the seasoning is deeply browned. Flip gently and sear for an additional 1-2 minutes, until fully cooked. 

3. Garnish and serve

Serve blackened mahi fillets with lemon wedges and Tartar Sauce.

What kind of fish is Mahi Mahi?

Mahi is a dolphinfish (not related to dolphins!). It's a firm, white fish similar to halibut. Most often you will find it frozen in airtight packets in the freezer section of your grocery store.

What is in blackening season?

It’s typically a spice blend made with traditionally "Cajun" flavors. In my blackening seasoning I use a blend of garlic powder, onion, paprika, smoked paprika, oregano, thyme, cayenne pepper, salt, sugar and black pepper. 

Can I use oil instead of butter to blacken fish?

You can use a neutral, high-heat oil instead of butter. But the process of blackening fish depends on the milk solids in the butter to accelerate the "blackening" process. So try it with butter first for the most authentic flavor.

How to store blackened Mahi Mahi?

Store leftover fish fillets in an airtight container and store in the refrigerator for up to 2 days. Serve leftovers with Mango Salsa and corn tortillas for fantastic Fish Tacos.

What to serve with blackened fish?

Serve blackened Mahi with Garlic Green Beans and Mashed Potatoes. Or whip up Creamy Cajun Sauce and Crispy Grit Cakes for a proper Southern supper.

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