Easy Oven Baked Flounder

Getting a tasty fish dinner on the table during busy weeknights can feel like quite the challenge. Between homework help, after-school activities, and the general evening rush, finding time to cook something both healthy and crowd-pleasing isn’t always easy.

That’s why this oven baked flounder has become such a reliable go-to in our house – it’s quick to prepare, turns out great every time, and lets you focus on other things while it cooks. Plus, it’s the kind of simple, good-for-you meal that makes you feel good about feeding your family.

What Kind of Flounder Should I Use?

When shopping for flounder, you’ll typically find either summer flounder (also called fluke) or winter flounder at your local fish counter. Both types work great for this recipe, though summer flounder tends to be slightly thicker and meatier. If you can’t find flounder, sole makes an excellent substitute since it has a similar mild, sweet flavor and delicate texture. Look for fillets that are firm and translucent with a mild ocean smell – avoid any that appear yellowish or have a strong fishy odor. Since flounder is quite thin, make sure not to buy pieces that are too small, as they can overcook quickly in the oven.

Options for Substitutions

This fish dish is pretty adaptable and here’s what you can swap if needed:

• Flounder/Sole: Any mild white fish works great here – try tilapia, cod, or halibut. Just watch the cooking time as thicker fillets might need a few extra minutes.
• Zucchini: Not a fan of zucchini? Yellow squash works perfectly, or try bell peppers or asparagus cut into similar sizes.
• Red onion: Yellow or white onions can step in for red onion. Shallots are great too – use 2-3 medium ones.
• Parmesan cheese: Romano or Pecorino make good stand-ins for Parmesan. For a dairy-free version, try seasoned breadcrumbs mixed with nutritional yeast.
• Lemon juice: If you’re out of fresh lemons, lime juice works too. You can also use 3-4 tablespoons of bottled lemon juice, though fresh is better.
• Olive oil: Any neutral oil like avocado or grapeseed oil will work, though you’ll miss some of that olive oil flavor.

Watch Out for These Mistakes While Baking

The biggest challenge when cooking flounder is preventing it from becoming dry and rubbery – this delicate fish needs only 10-12 minutes in the oven at 400°F, and overcooking even by a few minutes can ruin its tender texture. A common error is not patting the fish dry before seasoning, which can lead to a watery dish and prevent proper browning – take a moment to thoroughly dry the fillets with paper towels. For the vegetables, avoid cutting them too thin as they’ll cook faster than the fish and become mushy; stick to the recommended 1/2-inch thickness to ensure everything cooks evenly. To get the most flavor, don’t skip the marinating step – letting the fish sit with the seasoning and lemon juice for 15-20 minutes (but not longer, as the acid will start cooking the fish) allows the flavors to really sink in.

What to Serve With Baked Flounder?

This light and flavorful baked flounder pairs perfectly with simple side dishes that won’t overpower the delicate fish. A scoop of fluffy white rice or couscous makes an excellent base to soak up all those tasty Mediterranean-style juices from the fish and vegetables. For extra veggies beyond the zucchini that’s already in the dish, try serving it with roasted asparagus or a fresh Greek salad on the side. If you’re looking to keep things low-carb, cauliflower rice works great too, and don’t forget some extra lemon wedges on the table – a little extra citrus brightness is always welcome with fish!

Storage Instructions

Keep Fresh: If you have any leftover baked flounder, place it in an airtight container and pop it in the fridge. It’ll stay good for up to 2 days, though fish is usually best enjoyed the day it’s made. The zucchini and onions can be stored right along with the fish.

Prep Ahead: Want to get a head start? You can slice all your veggies and mix the seasonings up to a day in advance. Store the prepped vegetables in the fridge in an airtight container, and keep your seasoning mix in a small bowl covered with plastic wrap until you’re ready to cook.

Warm Up: To enjoy your leftover flounder, gently warm it in the microwave at 50% power in 30-second intervals until just heated through. You can also warm it in a covered baking dish in a 275°F oven for about 10-15 minutes, but be careful not to overheat it, as fish can dry out quickly.

Preparation Time	10-15 minutes
Cooking Time	10-15 minutes
Total Time	20-30 minutes
Level of Difficulty	Easy

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 1200-1400
• Protein: 90-100 g
• Fat: 80-90 g
• Carbohydrates: 20-25 g

Ingredients

• 1 1/4 pounds flounder fillets (sole can be used too)
• 2 medium-sized zucchini, halved and sliced into 1/2-inch half-moons
• 1 small red onion, halved and sliced into 1/2-inch half-moons
• Salt and black pepper to taste
• 3 minced garlic cloves
• 2 teaspoons oregano, dried
• 1/2 teaspoon paprika
• 1/2 teaspoon cumin
• Juice from 2 lemons (additional lemon wedges for serving)
• 1/4 cup to 1/3 cup extra virgin olive oil
• 1/2 cup parmesan cheese, grated

Step 1: Prepare the Oven and Ingredients

Preheat your oven to 350 degrees F.

While the oven is heating, pat the fish fillets dry with paper towels to remove any excess moisture.

Season the fish generously with kosher salt and black pepper on both sides to enhance the flavor.

Step 2: Arrange the Fish and Vegetables

Place the seasoned fish in a large oven-safe pan.

Next, arrange the zucchini and onions around the fish in the pan.

Season the vegetables with a little more salt and pepper to taste, ensuring they will be flavorful when roasted.

Step 3: Prepare and Add the Sauce

In a small mixing bowl, combine minced garlic, your choice of spices, fresh lemon juice, and olive oil.

Whisk these ingredients together until well-blended to create a fragrant and flavorful sauce.

Pour the sauce evenly over the fish and vegetables in the pan, coating them entirely with the mixture.

Step 4: Initial Baking

Place the pan in the preheated oven and bake for about 7 to 10 minutes.

Monitor the process carefully to ensure the fish does not overcook, particularly if you are using thin flounder fillets, which cook quickly.

Step 5: Add Parmesan and Final Baking

After the initial baking, carefully remove the pan from the oven and sprinkle grated Parmesan cheese over the fish and vegetables.

Return the pan to the oven and continue baking for another 3 to 5 minutes, or until the fish becomes flaky and the cheese has melted slightly.

Step 6: Serve and Enjoy

Once finished, remove the pan from the oven, being cautious of the hot surfaces.

Allow the dish to rest briefly before serving.

Enjoy your delicious fish and vegetable bake with a side of your choice!