A homemade Cajun spice mix adds incredible flavor to this Blackened Mahi Mahi. It’s a quick dish you can easily pull together on a busy weeknight but it’s so tasty you’ll want to serve it to guests!
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This is a new recipe for me and it came about after Paul and I had a meal at a nearby restaurant. We both ordered the mahi mahi special that was served with mashed sweet potatoes and veggies, and then we basically freaked out about how good it was for at least two days after and it haunted us in our dreams…. we’re weird.
This all had me wondering why the heck I never make mahi mahi at home. So, of course, I had to make some mahi mahi.
I set out to capture the same flavors we had in the restaurant dish and knew I definitely had to pair it with sweet potatoes, just like they did. The sweetness perfectly complements the slightly spicy fish in a soul-satisfying way. It’s truly a perfect flavor combination and it also happens to be SO good for us.
Say hello to my new favorite item from Costco. This great big package of Wild Caught Mahi Mahi contains skinless, individually vacuum-packed portions of incredibly fresh mahi mahi. I pop this bag in my freezer and pull just the number I need. The fish is FRESH, people. There is zero fishy aroma in the house after cooking it.
Mahi Mahi is a mild, firm textured white fish that is wonderfully tender – almost buttery – when prepared properly. It’s a fabulous source of lean protein and packed with nutrition. If you’ve got young ones who are squeamish about seafood, this would be a great one to try on them. Yes, blackened fish can be quite spicy. but when you make your own spice mix you get to decide precisely how spicy you’d like it. I’ll show you how!
To make the Kickin’ Cajun Seasoning Mix, grab a small bowl and combine 1½ teaspoons onion powder – 1 teaspoon each of smoked paprika, oregano, granulated garlic or garlic powder, thyme, and salt – and ½ teaspoon each of black pepper and cayenne pepper. The only spicy item here is the cayenne so feel free to adjust the amount to suit your taste. At ½ teaspoon, the fish will be mild to moderate on the spice scale. I’m a bit of a wimp and it is perfect for me. If I had little ones, I’d reduce it to ¼ teaspoon or even eliminate it all together. My big boys would tell me to add more!
Update – By popular demand I’ve published a recipe for a big batch of the Kickin’ Cajun Seasoning Mix. Check out the post for other delicious ways you can use this flavor-packed blend.
If you are using frozen mahi mahi, be sure to allow it to thaw completely (24 hours) in the refrigerator. Pat the fillets dry with paper towels so the spice mix will adhere nicely.
Sprinkle both sides of the fillets with the spice mix and use your clean hands to pat the mixture into the flesh of the fish. Then, of course, wash those hands again.
Melt 2 tablespoons butter and 1 tablespoon olive oil in a large skillet over medium-high heat. Get the pan as hot as it can get, without burning the butter, and then add the seasoned mahi mahi. You want that nice sizzle when the fish hits the pan. Cook it a good 3 or 4 minutes on one side until nicely golden brown, then flip it and let it go a few minutes on the other side. You don’t want to overcook it so be vigilant and pull the pan off the heat just as soon as it’s cooked through and flakes easily with a fork.
Remove the fish to a serving platter and squeeze fresh lemon juice over the top. A little citrus is a necessary thing when cooking fish as far as I’m concerned.
Oh, and before I go, if you’d like to serve this with mashed sweet potatoes, here’s how I did it. Place a couple of red-skinned sweet potatoes in a large pot and cover with water. Bring to a boil, reduce the heat and bring the water to a nice simmer and cover the pot. Cook the potatoes for 45 minutes to an hour, or until they pierce easily through with a knife. Remove from the pot to cool for just a couple of minutes. Use paper towels to pull the skin off and then mash the potatoes with a touch of light sour cream and salt. Perfect every time.
If you love mahi mahi, be sure to check out my Mahi Mahi with Lemon Butter Sauce. It has an entirely different but utterly delicious flavor profile.
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Blackened Mahi Mahi
Video
Ingredients
- 4 mahi mahi fillets, approximately 6 ounces each
- 2 tablespoons butter
- 1 tablespoon olive oil
- 1 lemon
Kickin’ Cajun Seasoning Mix:
- 1 ½ teaspoons onion powder
- 1 teaspoon garlic powder
- 1 teaspoon smoked paprika
- 1 teaspoon dried thyme leaves
- 1 teaspoon dried oregano leaves
- 1 teaspoon fine grain sea salt
- ½ teaspoon freshly ground black pepper
- ½ teaspoon cayenne pepper, or to taste
Instructions
- Combine all Kickin’ Cajun Seasoning Mix ingredients in a small bowl.
- Pat fillets dry with paper towels. Season the fillets liberally with Kickin’ Cajun Spice Mix on both sides, pressing the seasoning into the fish with your hands. Wash hands thoroughly.
- Place a large saute pan over medium-high heat and add butter and oil. When the fat is nice and hot, add the seasoned fish. Cook, undisturbed, for several minutes, until golden brown on one side. Flip fish over and continue to cook until opaque and completely cooked through.
- Squeeze lemon juice over the fish and serve.
Notes
Nutrition
Nutrition information is automatically calculated using generic ingredients, and is an estimate not a guarantee. For more accurate results, please refer to the labels on your ingredients at home.
Like this? Please rate & comment below!
Very quick and tasty. I reduced the cayenne to 1/4 t and increased the oregano and thyme. It was delicious.
Yummy recipe! Next time I will add more cayenne…needs more heat. I also tried the oven/cast iron skillet method of cooking. Super easy! Tomorrow I’m off to Costco to pick up the frozen Mahi Mahi everyone has raved about. Thanks Valerie.
Glad you enjoyed it, Lizette! I just picked up two packages of the Mahi Mahi from Costco last week and I’m looking forward to making this very soon 🙂
Made this tonight using fresh mahi mahi filets. Worked great. Great spice rub and a very quick and easy dinner.
I love the spice mix! I’m going to mix up a batch and store it in a jar for an even faster dinner. Thank you!
This recipe is awesome, transforms ordinary into extrordinary. I use that same cajun spice mixture wand added 2 tbsp of panko for chicken stuffed with spinach and pepper jack cheese. Such an amazing spice mixture, thanks for posting.
You got it, Karin!
I used your blackened seasoning recipe. DELICIOUS! I cooked my fresh mahi mahi sous vide first with minced garlic, then seared it with your blackened seasoning and it was the best mahi mahi I’ve ever had. Thanks for the recipe!
Hi Alissa. That sounds incredible! I’m sure the sous vide made it butter soft. So glad you enjoyed the seasoning mix!
Have you ever tried this rub on other fish….I’m thinking salmon. I wonder how it would turn out??? I tried this recipe as written before and it’s EXCELLENT! Hubby and I loved it and it pairs perfectly with a sweet potato. I’ve also paired it with “garlic butter roasted carrots” from pintrest as well and those were to die for.
I haven’t tried it but I just know it would be fabulous on salmon! Those carrots sound yummy. It is really nice to pair blackened fish with a side that has a bit of sweetness to it – like sweet potatoes or carrots. Great choice! So glad you and your hubby are loving it 🙂
This was AWESOME! I’m not a huge fan of spice but I do like a little more these days than I used to. I made it exactly as you have written, It was excellent but a tad bit too spicy to my liking so I will reduce the cayenne to 1/4 teaspoon next time and I’m pretty sure it will be perfect for what we like 🙂 Thanks for sharing my husband and my son both really liked the flavor of this recipe!
That’s great, Jodi! We really love this dish as well and it has become a regular on our menu. Thanks so much for your wonderful comment 🙂
Hi Valerie, I love this recipe and I cook in my oven at 425 degrees, in a very hot iron skillet. I place a tablespoon and one-half of a tablespoon of oil (I use canola as olive oil smokes at that temp) into my iron skillet. I placed in the pre-heated oven while I prepare my Mahi-Mahi. I have been purchasing this fish from COSTCO for a few years now is,,,, it is wild caught in U.S. waters. Once I have my fish coated, I take the skillet out and put the fish into the hot skillet….it just sizzles! I put it back in the oven for approx. 6 minutes, take out and flip the Mahi Mahi over and sprinkle a little more of the rub (or if in a hurry, I used Old Bay Blackening Seasoning…no other) and put back in the oven and cook another 5-6 minutes or until it is a little crispy around the edges, though not too much. It is one of my husband’s favorite dinners.
It sounds wonderful, Lynn. Aren’t those filets from Costco just the best? I’ve been preparing both the mahi mahi and salmon about once a week since I’ve discovered them. So fresh and honestly the best tasting fish I’ve found anywhere. Thanks for all your great tips!
Try avocado oil for non breaded frying. Its better for you than canola, and adds a bit of flavor. Works well with “blackened” recipes. I used it for this and ?.
This was absolutely amazing!! Used th Kirkland Mahi also, used 3 for the recipe, was barely enough rub though, I think this recipe is really for two but I put it on thick. We both love it. Followed the recipe exactly. Cooked in a cast iron skillet, 4 min per side. Whipped sweet potatoes were a great add with coleslaw. Thank you!
Hi Deborah! So glad it worked out for you. Made as directed it does make a very light coating of the rub. I often times will double it if I really feel like laying it on thick so thank you for mentioning this. This was on our menu this week too!
This was really good! I had just taken a couple of the Kirkland Mahi fillets out of the freezer and decided to look for a recipe! I upped the cayenne, but next time I’ll stick with your recommendation. It was just a little too spicy for me, but I’m a wimp!!
Hi Cathy. I’m with you on the wimp thing! A little cayenne goes a long way so I always try to hold myself back from using too much. It really is a very tasty seasoning mix and can be used on all sorts of things. I’m so glad you enjoyed it! Aren’t those frozen fillets from Costco the best? Thanks for the lovely comment 🙂
I love the blackened Mahi Mahi recipe! There is a Webber Cajun blend mix which I bought at Walmart. That is a time saver. Another blend I bought at Williams Sonoma and both are very good. Something else that saves me time: thaw the vacuum packed filets in a bowl of lukewarm water. Filets will be thawed in 30 min.
This is making me dream of summer, Valerie! Every year I love going fishing for mahi and it is one of my favorite foods. Yours looks amazingly delicious!