Blackened mahi mahi is a simple main course that's easy for weeknight meals and impressive enough to serve to company. Mahi mahi fillets are brushed in butter, coated in a flavorful seasoning blend, then seared on the stovetop until perfectly cooked and flaky.
Mahi mahi, also called dorado or dolphinfish, is a lean white fish (unrelated to the dolphin, which is a mammal). It has a mild, slightly sweet flavor and firm, flaky texture when cooked.
To prepare blackened mahi mahi, fish fillets are brushed in melted butter and seasoned with blackened, or blackening, seasoning. Then, the fillets are seared quickly on the stovetop to create a crisp crust.
Blackened mahi mahi makes a fantastic weeknight meal because it's ready in 20 minutes or less and packs plenty of flavor! Pair it with your favorite side dish, like my roasted potato arugula salad or creamy asparagus pasta, for a complete meal.
Ingredients and substitutions
- Mahi mahi fillets - For this recipe, you'll need about four 6-ounce mahi mahi fillets. Mahi mahi can be substituted with other types of firm white fish, like snapper, tilapia, or cod. Fish fillets can be frozen or fresh. If frozen, thaw completely before beginning recipe.
- Blackened seasoning - Feel free to use your own seasoning blend or buy blackened seasoning at the store. I've also included measurements to make your own in the recipe card. Blackened seasoning can also be substituted with cajun seasoning for a slightly spicier flavor.
- Unsalted butter - Melted butter is brushed onto the fish fillets before coating in blackening seasoning. This is an essential step in the blackening process because it helps the spices adhere to the fish. The milkfat solids in the butter also brown when seared to create that blackened crust.
- Vegetable oil - I recommend using a vegetable oil with a high smoke point, like avocado oil, canola oil, or peanut oil. Feel free to use your favorite.
- Lemon - After cooking, half a lemon is squeezed over the mahi mahi just before serving. This adds a bright, acidic flavor that pairs well with light fish.
Blackened seasoning, or blackening seasoning, is a blend of herbs and spices similar to a creole seasoning or cajun seasoning. For this recipe, I've used a blend of paprika, cayenne pepper, onion powder, salt, garlic powder, pepper, oregano, and thyme.
Blackened seasoning can be found in the spices aisle of your local grocery store or online: Amazon - Zatarain's Blackened Fish Seasoning. I've also included measurements to make your own in the recipe card below.
While the spices used are very similar, cajun seasoning tends to be a little bit spicier than blackened seasoning. However, they can be interchangeable in recipes if you don't mind the slight change in spice level and flavor.
What is blackening?
Blackening is the process of cooking a meat that has been brushed in melted butter, seasoned, and pan-seared quickly in a skillet. While this process doesn't actually burn the spices, they (along with the milkfat solids in the butter) do turn a dark brown and create a crisp crust on the outside of the cooked meat.
What to serve with mahi mahi
Wondering what to serve with your blackened mahi mahi? Here are a few of my favorite side dishes to serve with fish:
- Creamy asparagus bow tie pasta
- Roasted potato arugula salad
- Roasted potatoes and asparagus
- Parmesan orzo and peas
- Roasted zucchini and squash
- Southern coleslaw
Blackened Mahi Mahi
- 4 six-ounce mahi mahi fillets, if frozen, thaw first
- 2 tablespoons unsalted butter, melted
- 1 tablespoon blackened seasoning, *
- 1 tablespoon avocado oil, or other cooking oil
- ½ lemon
*To make blackened seasoning:
- 1 teaspoon paprika
- ½ teaspoon cayenne pepper
- ½ onion powder
- ½ teaspoon salt
- ¼ teaspoon garlic powder
- ¼ teaspoon pepper
- ⅛ teaspoon dried oregano
- ⅛ teaspoon dried thyme
- Pat mahi mahi fillets dry on both sides. Brush with melted butter, then season well on all sides with blackened seasoning.
- In a cast iron (or stainless steel) pan over medium to medium-high heat, add oil. When hot and shimmering, add seasoned fillets and cook for about 3-4 minutes per side, or until golden brown and fish is cooked through to your liking. Fish should flake easily with a fork in the center.
- Remove from heat, squeeze fresh lemon over fish, and serve warm.
- Feel free to use store bought blackened seasoning, your own blend, or the included recipe.
- USDA recommends that fish be cooked through in the center to 145 degrees Fahrenheit. For best results, I highly recommend using a meat thermometer. Once fish is removed from heat, transfer to a serving plate immediately to stop fish from cooking in the pan.