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 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).
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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!
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.
Pour the sauce mixture over the fish and vegetables to coat them well.
- 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.
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
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.
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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Easy Garlic Parmesan Baked Flounder Recipe (20 mins)
- 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 ⅓ cup extra virgin olive oil
- ½ cup grated Parmesan cheese
- 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).
- 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!
I had to make a couple of changes because I didn’t have zucchini or cumin, but nonetheless this dish was delicious!
I used frozen flounder…only it wasn’t quite thoroughly defrosted…nevertheless, I patted it dry and salted and peppered it…now here comes the substitution:all I could find which seemed to be doable here was a bag of frozen stir fry red potatoes, onions, and green peppers…I heated that in the microwave, then spread it over the fish…the sauce was missing only the cumin, but accidentally got a bit more oregano than called for….when baked the full time, after adding the Parmesan , the flounder was perfect! The taste, excellent…I could have easily helped myself to more! Thank you! This recipe is a keeper😊
Thanks for sharing your process, Joan!
I have made this several times and it is outstanding.
I agree with some of the comments. The vegetables did not cook in the same time as the fish. Definitely need to pre-cook the veggies. Just didn't taste great although I liked all the ingredients. Won't make it again.
Made this, n Ed longer cook time, but excellent!!!
I followed the times but fish, zucchini, and onions were undercooked. Adding salt to the veggies made the recipe very salty 🙁
Followed the recipe and ended up with undercooked fish swimming in liquid and still raw zucchini. Trying to fix it, but super disappointed.
I would cook the veggies a little before adding them to the fish. A can of artichoke hearts would be great to add.
Thanks for the feedback, Rhonda!
Great flavor. Roast the zucchini and onions separately otherwise they give up their water and sog the fish.
Thanks for the tip, Brent!