Here’s a restaurant-fancy meal you can make in about 20 minutes! One-pan baked flounder recipe with vegetables, flavored with a bold and lemony Mediterranean sauce and finished with grated Parmesan cheese! 

flounder recipe with vegetables in a baking pan.

Flounder 

Flounder is a white saltwater fish  with a mild flavor and a delicate, flaky texture. It is a low-mercury flatfish that is easy to work with, and you can cook it on the grill or sear it in a bit of good extra virgin olive oil (like I do with this trout). But, personally, I am a big fan of oven baked flounder, particularly if I’m working with thin fish filets (popping the fish in the oven and leaving it alone is the easiest way to keep it from falling apart).

What I love about this flounder recipe 

Today’s flounder recipe with vegetables is the kind of restaurant-fancy meal that takes one pan and only 20 minutes to make! A bold, lemony sauce loaded with flavor from garlic, good olive oil, and spices infuses the fish and vegetables with flavor, while keeping the fish moist as it cooks. No dry fish here! And the finishing sprinkle of nutty Parmesan takes it to the next level! Better than any baked fish you’ll have at a fancy restaurant, I promise! 

labeled ingredients for baked flounder recipe including flounder fillets, zucchini, red onion, olive oil, parmesan cheese, oregano, paprika, cumin, garlic, and lemon.

Ingredients for baked flounder 

With just a few ingredients, you’ll have the perfect baked flounder in no time! Here’s what you’ll need for this easy fish recipe:

  • Flounder fillet – You’ll need a 1 ¼-pound fillet. (See substitutions for flounder below.)
  • Vegetables – Zucchini and red onion, both cut into ½-inch half moon slices. 
  • Garlic – Mince 3 cloves of garlic to add the perfect garlicky kick to this baked fish. 
  • Spices – Dried oregano, paprika, and cumin add warmth and some earthiness. 
  • Lemons – You’ll need fresh lemon juice to brighten and lift the earthy flavors in this recipe for flounder, as well as some lemon wedges for serving.  
  • Extra virgin olive oil – ¼ to ⅓ cup EVOO is needed, so it’s best to use quality olive oil, like our mild but flavorful Italian Nocellara extra virgin olive oil
  • Parmesan cheese – I find that freshly grated parmesan is more robust than the pre-grated kinds, so I highly recommend buying a block and grating it yourself. 

What can I use if I can’t find flounder? 

If you can’t find flounder filet for this recipe, branzino, halibut, or sole are good substitutes. Choose thinner fish filets for this recipe. 

Both flounder and Dover sole are usually sold in thin filets, so both types of fish cook at similar speeds, meaning you won’t have to adjust the cooking time too much if you use sole instead of flounder. 

Really, though, any mild white fish filets will work in this fish recipe, like cod, trout, snapper, or even haddock.You may need to adjust the cooking time slightly. But no matter the type of fish you decide to bake, its internal temperature should be 140 to 145 degrees F when cooked. 

How to make baked flounder 

This is one of my favorite flounder fillet recipes because it requires minimal prep and is ready in about 20 minutes. Simply season the fish and vegetables, make the sauce, and bake! Here’s how to bake lemon garlic flounder:

  • Season the fish and vegetables. Pat 1 ¼ pounds of flounder fillets dry and season them on both sides with kosher salt and black pepper. Arrange the fish in a large oven-safe dish and add the vegetables (2 medium zucchini and 1 small red onion, both halved and sliced into half moons). Season the veggies with salt and pepper as well.  
  • Make the sauce. Whisk together 3 cloves minced garlic, 2 teaspoons dried oregano, ½ teaspoon each paprika and cumin, the juice of 2 lemons, and about ¼ cup extra virgin olive oil in a small bowl.

    sauce for baked flounder with garlic and parmesan.

    Pour the sauce mixture over the fish and vegetables to coat them well. 

    flounder fillets with sliced vegetables and sauce in a baking pan.
  • Bake the flounder and vegetables. Bake in a 350 degrees F heated oven for 7 to 10 minutes. Wearing oven mitts, remove the baking dish and sprinkle ½ cup grated parmesan over the flounder and veg. Place the pan back in the oven and bake for 5 minutes or so more until the flounder is flaky and the cheese has melted a bit. Remove from the oven and serve hot. 

Important tip for cooking flounder

Because flounder fillets are so thin, they overcook really quickly. So I recommend checking for doneness before the 10-minute mark. If you find that the fish is cooking quickly, add the Parmesan cheese sooner so you still have a little time for it to melt. 

recipe for flounder including baked flounder fillets and vegetables in a baking dish.

What goes well with flounder? 

The beauty of a mild-flavored fish like flounder is that it goes with many different things. We’ve already included zucchini and onions in the same pan with the baked fish, but there are many other sides to choose from.

Potatoes are great to serve with baked flounder. Try my herby boiled potatoes or smashed potatoes

Other green sides to go with this baked fish recipe are: roasted broccoli, Greek green bean salad, or this asparagus salad

Leftovers and storage

Leftover cooked flounder will keep in an airtight container in the fridge for up to 2 days. I prefer to eat leftover fish at room temperature so it doesn’t become overcooked with reheating. But if you like, you can add everything to a skillet over medium-low heat for a few minutes until just heated through. 

Flounder recipe FAQs

How do you know when flounder is cooked?

Fish is cooked when it has reached an internal temperature of 140 to 145 degrees F. Keep in mind that fish continues to cook after being removed from the oven, so it’s better to take it out two or so minutes early. It will finish cooking as it rests. If you don’t have a meat thermometer, look at the color and texture of the fish. Cooked white fish flesh will turn from opaque to white, and will flake easily with a fork. To avoid dry flounder, keep a close eye on it after it has been in the oven for 7 to minutes.

Can I use frozen flounder instead of fresh flounder in this fish recipe?

Yes, you can use frozen flounder in this recipe. Just be sure to thaw it overnight in the refrigerator, and pat it dry thoroughly to remove excess moisture.

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4.32 from 89 votes

Easy Garlic Parmesan Baked Flounder Recipe (20 mins)

A picture of Suzy in the kitchenSuzy Karadsheh
recipe for flounder including baked flounder fillets and vegetables in a baking dish.
This one-pan baked flounder recipe with garlic, Parmesan cheese, and vegetables is easy and so delicious (thanks to a bold and lemony sauce with Mediterranean spices!). If you can't find flounder, any mild white fish would work, such as Dover sole, halibut, or branzino filet will work. Choose thinner fish filets if possible. Serve baked flounder with potatoes or greens like broccoli or a green bean salad.
Prep – 5 minutes
Cook – 15 minutes
Total – 20 minutes
Cuisine:
Mediterranean
Serves – 6 people
Course:
Dinner

Ingredients
  

  • 1 ¼ pound flounder fillet, sole fillet will also work
  • 2 medium zucchini, halved and cut into ½-inch slices (half moons)
  • 1 small red onion, halved and cut into ½-inch slices (half moons)
  • Kosher salt and black pepper
  • 3 garlic cloves, minced
  • 2 teaspoons dried oregano
  • ½ teaspoon paprika
  • ½ teaspoon cumin
  • Juice of 2 lemons, plus more lemon wedges for serving
  • ¼ cup to 1/3 cup extra virgin olive oil
  • ½ cup grated Parmesan cheese

Instructions
 

  • Heat the oven to 350 degrees F.
  • Pat the fish dry and season it well with kosher salt and black pepper on both sides. Arrange the fish in a large pan and add the zucchini and onions next to it and season them with salt and pepper.
  • In a small mixing bowl, add the garlic, spices, lemon juice, and olive oil. Whisk to combine.
  • Pour the sauce all over the fish and vegetables.
  • Bake in the heated oven for 7 to 10 minutes, then carefully remove the pan and sprinkle the grated parmesan all over the fish and vegetables. Return the pan to the oven and bake for another 3 to 5 minutes or so until the fish is flaky and the cheese has melted some. (Flounder fillets are thin and should not take too long to cook. Be careful not to overcook them).

Notes

  • Substitutes for flounder: Branzino, halibut, sole, cod, trout, snapper, or haddock — any mild white fish would work. Just be sure to use thin fish filets.
  • Tip for success: Flounder fillets cook very quickly, so check after it has been baking for 7 minutes or so. If you find that the fish is cooking faster than expected, add the Parmesan sooner to give it some time to melt. 
  • Can you use frozen flounder in this recipe? Yes, just be sure to thaw it overnight in the fridge. And pat it dry to remove excess moisture. 
  • Serve baked flounder with: Try my herby boiled potatoes or smashed potatoes. For a green side, try roasted broccoli, Greek green bean salad, or this asparagus salad
  • Leftovers and storage: Store leftovers in an airtight container in the fridge for up to 2 days. I prefer to eat leftover fish at room temperature. But you can add everything to a skillet over medium-low heat for a few minutes until just heated through. 
  • Visit our shop to browse our all-natural and organic spices (like the paprika and cumin used in this recipe), olive oils, and much more!

Nutrition

Calories: 204.3kcalCarbohydrates: 5.9gProtein: 15.4gFat: 13.5gSaturated Fat: 3gPolyunsaturated Fat: 1.5gMonounsaturated Fat: 7.6gTrans Fat: 0.1gCholesterol: 49.8mgSodium: 326.2mgPotassium: 385.1mgFiber: 1.4gSugar: 2.5gVitamin A: 330IUVitamin C: 13.6mgCalcium: 123.6mgIron: 1mg
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I’m Suzy; born and bred right on the shores of the Mediterranean. I’m all about easy, healthy recipes with big Mediterranean flavors. Three values guide my cooking: eat with the seasons; use whole foods; and above all, share! So happy you’re here…
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4.32 from 89 votes (45 ratings without comment)

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Comments

  1. Brenna says:

    4 stars
    The flavors were wonderful but I was worried the zucchini wouldn’t cook in time. I was right. I ended up taking the fish out after ten minutes and then turning it up to to 400 to cook the veggies for another ten to fifteen. It was really tasty but next time I’ll cook the vegetables first.

  2. Barbie C says:

    5 stars
    This was really delicious. I cooked it at 400 for a bit longer and made sure the zucchini and onions weren’t too thick. Used frozen tilapia from Trader Joe’s. Only had one lemon and mistakenly used ground coriander instead of cumin. It was incredible and so easy! My dubious husband even gave it a thumbs up and he generally doesn’t care for onions. This is definitely going into the rotation. Thank you for all you do.

    1. Suzy says:

      Wonderful! Thanks, Barbie!

  3. Natalie says:

    The fish was delicious but the vegetables were completely under cooked.

  4. Diana says:

    Hi There, my husband cannot eat anything with seeds. What would be a good substitute for the zucchini?

    1. Suzy says:

      Hi, Diana. You can really use any other vegetables that you all enjoy that are safe for your husband to eat in this one. It’s a very forgiving recipe.

  5. Vera says:

    I haven’t made this dish yet but I know it will be yummy. Just why the recipe has 22 pages???
    Also, I want to commend you on your cookbook. I bought is and am loving it. The photos and hints are invaluable. Thank you Suzy!

  6. Amy Reeb says:

    1 star
    I did not care for this dish at all. I thought 2 cups of lemon juice might be too much so I used 1 and a half cups and it was still too much. It was very tart and sour. The lemon overpowered all the other flavors. I will not make this again,

    1. Erin says:

      It says juice of 2 lemons. Not 2 cups of lemon juice.

  7. Amy Reeb says:

    1 star
    I didn’t think this dish was good at all! I thought 2 cups of lemon juice was too much so I used 1.5 cups. It was still too sour! None of the other flavors come through because all you can taste is tart lemon. I won’t be making this again.

  8. sandra says:

    3 stars
    I should have read the comments before I made this. The vegetables came out totally raw – I had to pull them off and sauté them separately.

    1. Mike says:

      I thought it wasn’t enough cooking time
      And maybe 400 would be better but your e right especially the raw garlic

    2. Natalie says:

      Same

  9. Shaniece says:

    4 stars
    Really, really delicious dish!! Bright and rich at the same time, plus–it’s healthy…ish..lol. Will definitely make again, including for company.

    1. Suzy says:

      Yay! Glad to hear it, Shaniece!

  10. Barbara says:

    4 stars
    Healthy, clean, easy, delicious!

  11. Wendy says:

    5 stars
    I made this tonight for my Mom and daughter, we all loved it. Light and tasty and I have added to our favorites. This is a wonderful recipe if looking for an alternative to fried fish. I did however, saute my veggies for about 5 minutes. I didn’t think the veggies would cook to my liking otherwise, and they still came out crunchy and cooked to my desired crispiness.

    1. Suzy says:

      Thanks for sharing, Wendy! So glad you enjoyed it!

  12. Rich G says:

    When you sprinkle the cheese on do you flip the flounder and do both sides.

    1. Suzy says:

      Hi, Rich. Nope… just sprinkle it on top. Hope you enjoy the recipe!

  13. Debora says:

    5 stars
    Superb fish dish!! Very tasty with the spices and zucchini. Only had basa filets but nevertheless turned out very well. Will definitely be in dinner rotation. Served with brown rice and black beans and salad.

    1. Suzy says:

      Sounds perfect! Thanks, Debora!

  14. Laurie says:

    “Sort of” making this tonight. Sorry, Suzi, I’m winging it but based on your recipe! We’re using haddock instead of flounder (yes, I’m watching the thickness thing) and I only had half an onion for fresh veggies, so I quick-thawed some broccoli and Brussels Sprouts in the microwave and put them in. I was going to put mini mixed color peppers in, but the baking tray was full so i left them out. I’ll come back later and let you know what hubby thought about it!

    1. Suzy says:

      Hope you enjoyed it, Laurie!

  15. Maggie says:

    5 stars
    Already made it tonight! Delish! I was concerned the veggie’s wouldn’t be cooked so I used same pot and sauted first. Came out perfect

    1. Ann Marie says:

      I was also thinking 7-10 min would not be enough time to cook the veggies.

    2. Suzy says:

      So glad you enjoyed the recipe, Maggie!

  16. Lauren says:

    5 stars
    Love a good one-pan meal!

    1. Suzy says:

      Enjoy!