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!
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
- 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
- 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.
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.
Questions and Reviews
This was SO good. And easy! I had just purchased some frozen mahi and was trying to figure out how to prepare it. This recipe – plus the suggestion to serve w mashed sweet potatoes (which I also had on hand and made quickly in the instant pot) – was fantastic. I am going to pat myself on the back and say it was restaurant quality. Thank you for sharing!
So good! So easy! So fast! Uses spices you already have! Takes less than 15 minutes from start to finish! I served it with leftover butternut squash and steamed spinach. Perfect weeknight dinner.
Nice meal but poor instructions. Cook on one side for “serveral minutes” and then on the other side “until done” is a bit vague for fish.
Hi Mark. The instructions read “Cook, undisturbed, for several minutes, until golden brown on one side. Flip fish over and continue to cook until opaque and completely cooked through.” Sorry you had trouble but glad you enjoyed the recipe.
Made Mahi for the family to night! Left out the cayenne & subbed a teaspoon of whole fennel & 1/2 a teaspoon of caraway seed (my mom doesn’t like spicy food). It turned out delicious. Scored the sweet potatoes & boiled in water with about 12 whole cloves & two split cardamon seed pods… the fragrance enhances the sweet potatoes! Served with a roasted brussel sprouts (doused with evoo & balsamic vinegar… Delicious, fall dish!
This recipe is the BOMB! Definately a keeper…the spices really make the Mahi Mahi pop. Made it exactly as written and the outcome was superb.
Perfect thank you. I like blackened food and your recipe for the seasoning mix was spot on. I will try with sweet potatoes, that sounds great, I had the fish with asparagus in butter and lemon sauce and a pineapple salsa, equally fantastic.
Love this with a fruit salsa! Such a great combo. Thanks for your comment, Terry 🙂
I haven’t had mahi-mahi in years, but there was a fresh wild catch on sale at my local store today so I grabbed some. Then I Googled recipes, tried yours, and…just, wow! I didn’t even have the smoked paprika, but I’ll be sure to for next time. Now if I can just get my kids on board. 🙄 Thanks, Valerie!
I live in Maui and my neighbor fishes for Mahi and Ono on a regular basis. I made this recipe tonight and served it on a caesar salad and both my husband and I said it was the best blackened fish we have ever made. Thank you!!!
Could I grill this?
Happened to buy the same Mahi filets from Costco and was looking for a recipe. Turned out great! Definitely recommend this spice blend.
Best Blackened recipe I have ever tried, and I have tried many!!! Will definitely use it again and again.
Delicioso!! My family loved this. Simple to make and great tasting!
After cooking fish, I added another tbsp of olive oil and cooked some onions, garlic and red and orange peppers. The flavors left in the pan with the additional complimented the fish and sweet potato!
Thank you so much!
Love your additions! Thanks, Maria 🙂