Baked Flounder with Garlic and Parmesan

Baked flounder is a one-pot, restaurant-worthy meal you can make in about 20 minutes! Fish fillets are seasoned, then baked with vegetables and a bold lemony Mediterranean sauce and finished with Parmesan! 

What I Love About this Flounder Recipe

When I created this baked flounder recipe with vegetables, I wanted something that felt fancy, but didn’t take all evening to make. 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 cooks quickly because it’s so thin.

I whipped up a bold, lemony sauce with garlic, extra-virgin olive oil, sweet paprika, and oregano to infuse the fish and vegetables with flavor while keeping it moist as it cooks. No dry fish here! The finishing sprinkle of nutty Parmesan cheese adds a textural element and a little salty bite! It’s 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 fillets: You’ll need 1 1/4-pounds of fish fillets.
• Vegetables: Zucchini and red onion, both cut into 1/2-inch half-moon slices. 
• Garlic: 3 minced garlic cloves add the perfect garlicky kick to this baked fish recipe. 
• Spices: Dried oregano, sweet paprika, and cumin add warmth and some earthiness. 
• Lemons: You’ll need fresh lemon juice to brighten and lift the earthy flavors, as well as lemon wedges for serving.  
• Extra virgin olive oil: 1/4 to 1/3 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. 

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!

• Make the sauce. Whisk together 3 cloves minced garlic, 2 teaspoons dried oregano, 1/2 teaspoon each sweet paprika and cumin, the juice of 2 lemons, and about 1/4 cup extra virgin olive oil in a small bowl.
• Season the fish and vegetables. Pat 1 1/4 pounds of flounder fillets dry, and season on both sides with kosher salt and black pepper. Arrange the fish in a large oven-safe dish, and add 2 medium zucchini and 1 small red onion, both halved and sliced into half moons. Season the veggies with salt and pepper as well. Pour the sauce over the fish and vegetables to coat. 
• Bake the flounder and vegetables. Place the baking dish in a 350°F heated oven for 7 to 10 minutes. Remove the baking dish from the oven and sprinkle 1/2 cup grated Parmesan over the flounder and vegetables. Place the dish back in the oven and bake for 5 minutes more until the flounder is flaky and the cheese has melted a bit. Remove from the oven and serve hot. 

Flounder Tips

• Don’t overcook the fish! Flounder fillets overcook quickly because they are so thin. I recommend checking for doneness before the 10-minute mark. If you find the fish is cooking quickly, add the Parmesan cheese sooner so you still have a little time for it to melt. 
• Flounder Substitutions: If you can’t find flounder fillets for this recipe, branzino, halibut, trout, or sole are good substitutes. You want thin 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, so you won’t have to adjust the cooking time too much. 
• How do you know when flounder is cooked through? Fish is cooked when it has reached an internal temperature of 140-145°F. Keep in mind the fish will continue to cook after being removed from the oven, so it’s better to take it out closer to 140°F and let the carryover cooking finish the job. Check the temperature after about 7 minutes.
• If you don’t have a thermometer, look at the color and texture of the fish. The fish will turn from opaque to white and flake easily with a fork.

Swaps and Substitutions

• Can I use frozen flounder? Yes! Frozen flounder works great in this recipe; just thaw it in the refrigerator 24 hours before you make this recipe.
• If you have to swap a thicker fish, any mild white fish filets will work in this recipe, like cod, snapper, or even haddock. You may need to increase the cooking time by 5 or 10 minutes, depending upon the thickness of the fish you choose. Always check the internal temperature, which should be between 140-145°F when ready to remove from the oven. 
• Swap the vegetables: If you don’t have zucchini, use yellow summer squash, or other tender vegetables like asparagus, green beans, or colorful bell peppers.

What to Serve with Baked 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 with the baked fish, but there are many other sides to choose from.

• Try my herby boiled potatoes or smashed potatoes. 
• For less starchy vegetables, try roasted broccoli, Greek green bean salad, or this asparagus salad. 
• Add a grain or pasta like pearl couscous, basmati rice, or this easy lemon pasta.

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. You can toss everything in a skillet set over medium-low heat for a few minutes until just heated through. 

Baked Fish Recipes to Try Next

Fish and Seafood

Stuffed Flounder with Tomatoes, Roasted Red Peppers, and Olives

Fish and Seafood

Poached Flounder with Sweet Corn Salsa

Entree

Baked Sole Fillet, the Mediterranean Way

Fish and Seafood

Baked Trout with Lemon, Garlic, and Fresh Herbs