Baked Flounder With Lemon and Butter

Baked flounder fillets with chopped parsley and lemon wedges in a baking dish

​The Spruce Eats / Ulyana Verbytska

Prep: 10 mins
Cook: 25 mins
Total: 35 mins
Servings: 4 servings
Nutrition Facts (per serving)
255 Calories
16g Fat
2g Carbs
26g Protein
Show Full Nutrition Label Hide Full Nutrition Label
Nutrition Facts
Servings: 4
Amount per serving
Calories 255
% Daily Value*
Total Fat 16g 20%
Saturated Fat 8g 41%
Cholesterol 126mg 42%
Sodium 1239mg 54%
Total Carbohydrate 2g 1%
Dietary Fiber 0g 2%
Total Sugars 1g
Protein 26g
Vitamin C 8mg 40%
Calcium 52mg 4%
Iron 1mg 4%
Potassium 379mg 8%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)

Flounder is a mild white saltwater fish that is delicious when baked. The flatfish is low in mercury, making it safe for pregnant women and kids of all ages to enjoy. Fillets can be purchased at the fish counter or frozen, and both will work for this recipe. If your flounder fillets are frozen, defrost them in the refrigerator overnight before using.

This recipe adds lots of flavor with lemon, paprika, and butter, while still highlighting the fish's mild taste. As the fish bakes, you'll have just enough time to whip up a sauce and side dishes. Flounder is especially good when served with homemade garlic aioli, or try it with a prepared tartar sauce or pesto instead. 

The recipe can be made with sole, haddock, or another mild white fish. Adjust the baking time if the fillets are quite thick; they may take a little longer. Serve the baked fish with baked potatoes or rice and a salad or steamed vegetables.


Click Play to See This Simple Baked Flounder Come Together

"This is the perfect weeknight fish recipe. Flounder is a delicious, mild white fish that takes on the flavor of what it’s cooked in, so the final product is light and goes great with the garlic aioli. If you are looking for a recipe for the fish-adverse, I would highly recommend this one." —Tracy Wilk

Baked Flounder With Lemon and Butter Tester Image
A Note From Our Recipe Tester


For the Flounder:

  • 1 1/2 pounds flounder fillets (or sole)

  • 1 teaspoon salt, or to taste

  • 1/8 teaspoon black pepper

  • 4 tablespoons butter, melted

  • 2 tablespoons fresh lemon juice

  • 2 teaspoons finely minced onion

  • 1 teaspoon paprika

  • 1 tablespoon fresh parsley, for serving

  • 4 slices or wedges lemon, for serving

For the Garlic Aioli (Optional):

  • 2 medium cloves garlic, optional

  • 1/2 cup mayonnaise, optional

  • 2 tablespoons olive oil, optional

  • 1 tablespoon fresh lemon juice, optional

  • Salt, to taste, optional

Steps to Make It

Prepare the Fish

  1. Gather the ingredients.

    Ingredients for baked flounder recipe with lemon and butter gathered

    ​The Spruce Eats / Ulyana Verbytska

  2. Grease a shallow baking dish. Preheat oven to 325 F/165 C.

    Shallow ceramic baking dish greased with butter

    ​The Spruce Eats / Ulyana Verbytska

  3. Cut the flounder fillets into serving-size portions. 

    Flounder fillets placed on paper towels and cut into serving-size portions with a large knife

    ​The Spruce Eats / Ulyana Verbytska 

  4. Arrange the pieces in the prepared baking dish, and sprinkle fish with salt and the freshly ground black pepper.

    Flounder pieces arranged in baking dish in a single layer and sprinkled with salt and black pepper

    ​The Spruce Eats / Ulyana Verbytska

  5. In a small bowl or measuring cup, combine melted butter, 2 tablespoons lemon juice, and minced onion.

    Melted butter, lemon juice, and minced onion combined in a small spouted bowl and stirred with a spoon

    ​The Spruce Eats / Ulyana Verbytska

  6. Pour the lemon-butter mixture over fish.

    Melted butter mixture being poured over the flounder pieces in baking dish

    ​The Spruce Eats / Ulyana Verbytska

  7. Sprinkle the fish with paprika.

    Paprika being sprinkled over the flounder in the baking dish

    ​The Spruce Eats / Ulyana Verbytska

  8. Bake in the preheated oven for about 15 to 25 minutes, depending on thickness of the fillets, or until fish is cooked through and flakes easily with a fork.

    Baked flounder being tested for flakiness with a fork

    ​The Spruce Eats / Ulyana Verbytska

  9. Garnish with chopped parsley, lemon wedges, and serve with garlic aioli (if desired).

    Baked flounder with chopped parsley and lemon wedges in a baking dish

    ​The Spruce Eats / Ulyana Verbytska

Prepare the Garlic Aioli (Optional)

  1. Gather the ingredients.

    Ingredients for garlic aioli recipe gathered

    ​The Spruce Eats / Ulyana Verbytska

  2. Place the garlic in a small bowl and mash well with a fork. Or mash it using a mortar and pestle.

    Garlic being mashed with a fork in a glass bowl

    ​The Spruce Eats / Ulyana Verbytska

  3. Add the mayonnaise, olive oil, and lemon juice and then whisk to blend thoroughly.

    Mayonnaise, olive oil, and lemon juice being added to garlic and stirred with a fork

    ​The Spruce Eats / Ulyana Verbytska

  4. Season with salt.

    Salt being added to the aioli

    ​The Spruce Eats / Ulyana Verbytska

  5. Cover and chill until serving time.

    Aioli in glass bowl covered with plastic wrap until ready to serve

    ​The Spruce Eats / Ulyana Verbytska


  • Fish can quickly become tough and dry if overcooked. If the fillets are very thin, check for doneness after about 10 to 15 minutes.
  • Thicker cuts of fish may take longer than 25 minutes to cook through. Start checking the fillets starting at 20 minutes, even if they are thick to prevent overcooking.


This technique with lemon and butter is basic and delicious, but feel free to play with other herbs and seasonings, either fresh or dried, instead of the parsley garnish.

  • Chives
  • Dill
  • Basil
  • Tarragon
  • Rosemary

How to Store Flounder

If you have leftovers, it's best to get them into the refrigerator as soon as possible. Keep the fish wrapped tightly or in a sealed container and it should be good for about 3 to 4 days.