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
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.
This recipe was just what I was searching for. My husband will soon have surgery and will be limited (not allowed) spicy foods for a couple months. He loves mahi mahi and I love spicy so its a compromise, but one I’m willing to take for his health benefit. I’ll leave the cayenne out (so sad) but I’ll make it for him and put the cayenne in again when he gets better. Thanks so much for this recipe.
Made this tonight using fresh Mahi Mahi – it was delicious!
This recipe is fantastic! I tried it the other day after I caught a mahi-mahi on the boat down near Mexico. I know your recipe called for the Kirkland mahi, but I just couldn’t pass up on the freshly caught one.
Valerie, if you think your readers would like to learn how to sustainably catch the fish they are eating, I’d be humbled and honored if you’d include the guide I wrote about it in this post: https://castandspear.com/dorado-fish/. I feel it’s always important to know where your food comes from.
P.S. I can’t wait to try more of your recipes 🙂
When my wife and I spent a week on Oahu last summer, we ate fresh mahi every day. It’s a wonderful fish. The Hawaiians don’t use blackening to my knowledge just mild seasoning.
Absolutely outstanding! Best fish I have ever made OR tasted- and I’ve made and tasted just about everything. 🙂
Fantastic, Eda! So glad you enjoyed it. 🙂
Hi Valeri,
I just got stationed in Okinawa Japan & the FRESH seafood that is available is just sick!
I’m a tru Kountry Boy for TN, Smoked everything that makes a sound. Except fish, 😉
So I decided to venture out & attempt my hand at seafood, since that is the dominant cuisine & came across, well you & your Mahi Mahi recipe. I will try it this weekend & post the results, good or bad.
One question though, your sweet potato recipe states to use “peeled” potatoes prior to boiling. Then it states after boiling to remove the skins. do I boil with or without skins? Thanks.
Hi Sean. There’s no need to peel sweet potatoes before boiling. They will practically fall right off once they are cooked. Hope you love the recipe!
fantastic recipe! Super easy and fast and a whole family loved it! I did a whole family loved it! I did take it easy on the Cayenne for the kiddos and it was still great! Thank you for the awesome recipe.
Blackened mahi-mahi is such a treat that even my finicky teen-age daughter loved it. So simple to prepare, delicious and nutritious. Costco ought to print your recipe right on the label. Added turmeric with excellent results and plan to add fenugreek to next batch. Guru insists it’s the miracle cure!
Since sweet potato takes such a long time to boil I cooked extra and kept them in fridge for several days. Easy to peel and mash cold, then heated for one minute on frying pan as soon as fish was removed. Used a pinch of cumin instead of sour cream.
Easy and delicious, my family enjoyed it. My twelve who is not a fan of fish gave this recipe a thumbs up! Thanks for sharing..
So easy & delicious! Husband loved it! Replaced cayenne with chili powder.
Just made this after a quick search turned up your recipe. So glad I found it. The Costco Mahi Mahi is a special treat I buy for myself two or three times a year but after tasting this I think the frequency is going to skyrocket. Oddly enough I had taken the fish out yesterday so I “had” to cook it tonight lest the fish go off in the fridge. None of us were hungry after a late afternoon lunch so the plan was to reheat tomorrow. Well, there’s only one piece left. I made one disappear and then my wife and two young daughters snacked away the other two. It was irresistible! Definitely going to make a big jar of the spice mix for quick Cajun taste on fish, chicken and probably pork too!
Yay, Kelly! So glad to hear you loved it. I’m endlessly impressed with the quality of Kirkland brand frozen fish. The salmon is wonderful too. Thanks so much for your comment. 🙂
Just a follow up for you. Tried it with pork tonight – same cooking method. Yum-yummy!
Besides the salmon and mahi mahi we also like Costco Tilapia Loins.
The recipe is just wonderful. Making it as written for the second time. A real family favorite.
Fantastic! So glad to hear this, Evelyn. 🙂
Got two lovely fillets of mahi mahi this morning. I’ve only made tacos with it before, so I went to the net for ideas. This is perfect, since I coincidentally, also bought sweet potatoes. Thanks for the idea. I will replicate it to the T!