Looking for a delicious and easy weeknight meal? Try my baked flounder recipe with pesto! Our flaky and tender fillets are lightly seasoned with butter, parsley, and a blend of simple spices, then topped with a rich and flavorful homemade pesto that elevates the otherwise mild flavor of the flounder.

What You Need to Make this Recipe
- Pesto: Top the fish with homemade pesto sauce. My recipe combines pistachios, basil, lemon zest, garlic, olive oil, and parmesan cheese. You can purchase store-bought pesto if you don’t feel like preparing your own.
- Flounder: I use frozen flounder filets from Costco. However, if you have access to fresh fish, use that instead. I defrost the fillets in the fridge the night before for easy preparation the next day.
- Spices: Lightly season the fillets with parsley, kosher salt, coarse ground pepper, and red pepper flakes.
Additions and Substitutions
Flavor the dish with butter and a mix of salt, pepper, red pepper flakes, and dried parsley. This mouthwatering combination creates a perfect base to highlight the pesto, but free to experiment with different herbs, such as rosemary or dill. If you want a spicier topping, consider using green skhug instead of pesto.
How to Make Our Baked Flounder Recipe
The full recipe with measurements is in the recipe card below.
Step 1: Prepare pesto before cooking the fish. Set it aside.

Step 2: Preheat the oven to 325°F (162°C). Then, combine the melted butter, parsley, salt, pepper, and red pepper flakes in a small bowl.

Step 3: Line the filets in a prepared baking dish.

Step 4: Brush them with the butter mixture using a pastry brush.

Step 5: Bake for 10-25 minutes. Cooking time will vary depending on the thickness of the filets (See Note).

Step 6: Top the baked flounder with homemade pesto and serve with a house salad or pilaf.

Expert Tips
- Flounder is a delicate fish. If using thin filets, I recommend checking for doneness at the 10-minute mark. Thicker cuts of flounder may take longer; consider baking them for 20-25 minutes.
SEARCHING FOR MORE LIKE THIS?
If you love this recipe, try one of our other seafood favorites!

Serving Suggestions
- Rice: White Rice, Rice Pilaf, Risotto, Quinoa
- Vegetables: Mashed Cauliflower, Grilled Zucchini
- Sides: Hush Puppies
- Salad: Vegetable Chopped Salad, Ceasar Salad, Arugula and Spinach Salad, Homemade Coleslaw with Mint and Cilantro, Vinegar Coleslaw
What to Do With the Leftovers
- Refrigerate – Store leftovers in an airtight container. Baked flounder will keep for 3-4 days.
- Reheat – Bring leftovers to temperature in the oven or cook them in the microwave for 30-40 seconds.
- Repurpose – Add leftover fish to rice or cauliflower rice to make a protein bowl, or transfer the fish to a fresh corn tortilla for a quick fish taco.
Frequently Asked Questions
What does flounder taste like?
Flounder has a delicate, mild flavor that’s slightly sweet. The flesh of the flounder is white, flaky, and tender.
How long to bake flounder?
If using thin filets, I recommend checking for doneness at the 10-minute mark. Thicker cuts of flounder may take longer. Consider baking those for 20-25 minutes and check them at the 20-minute mark.
How do you know when flounder is done?
Using our baked flounder recipe, the fish will be white and flaky after it finishes cooking.
What temperature should flounder be cooked to?
Use a food thermometer to check the internal temperature; the safe cooking temperature for flounder is 145°F (62°C).

Baked Flounder Recipe with Pesto
- Small Bowl
- 4 flounder fillets
- ¼ teaspoon parsley, dried
- ½ teaspoon kosher salt
- ½ teaspoon black pepper, coarse ground
- ¼ teaspoon red pepper flakes
- 2 tablespoons butter
For the Pesto:
- Prepare Pesto before cooking the fish. Set it aside.
For the Flounder:
- Preheat the oven to 325°F (162°C). Then, combine the melted butter, parsley, salt, pepper, and red pepper flakes in a small bowl.
- Line the filets in a prepared baking dish, and brush them with the butter mixture using a pastry brush.
- Bake for 10-20 minutes. Cooking time may vary depending on the thickness of the filets.
- Top the baked flounder with homemade pesto and serve with a house salad or pilaf.
- If using thin filets, I recommend checking for doneness at the 10-minute mark. Thicker cuts of flounder may take longer. Consider baking those for 20-25 minutes and check them at the 20-minute mark.
- The nutritional information shown is an estimate provided by an online nutrition calculator. It should not be considered a substitute for professional advice.
Ali
Friday 26th of May 2023
Great recipe!
Tressa Jamil
Monday 2nd of October 2023
I am thrilled you enjoyed it. Thank you for taking the time to rate the recipe and leave a comment.
Emily Reynolds
Friday 26th of May 2023
This baked flounder recipe is a weeknight dinner winner!The fillets melt in your mouth, and the homemade pesto adds so much flavor. My family loved it!
Tressa Jamil
Monday 2nd of October 2023
You are so right about the fillets melting in your mouth. I may need to add that to the post. I am so happy this is a meal your whole family enjoyed.