Baked Flounder With Lemon and Butter

Baked flounder with chopped parsley and lemon wedges

​The Spruce / Ulyana Verbytska

  • Total: 35 mins
  • Prep: 10 mins
  • Cook: 25 mins
  • Servings: 4 servings
Nutritional Guidelines (per serving)
555 Calories
43g Fat
14g Carbs
29g Protein
See Full Nutritional Guidelines Hide Full Nutritional Guidelines
Nutrition Facts
Servings: 4
Amount per serving
Calories 555
% Daily Value*
Total Fat 43g 55%
Saturated Fat 12g 61%
Cholesterol 137mg 46%
Sodium 875mg 38%
Total Carbohydrate 14g 5%
Dietary Fiber 1g 4%
Protein 29g
Calcium 115mg 9%
*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 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. Serve it with homemade garlic aioli or 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. Serve the baked fish with baked potatoes or rice and a salad or steamed vegetables.


  • 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 onion (finely minced)
  • 1 teaspoon paprika
  • For serving: fresh parsley and lemon wedges
  • For the Garlic Aioli (Optional):
  • 2 medium cloves garlic
  • 1/2 cup mayonnaise
  • 2 tablespoons olive oil
  • 1 tablespoon fresh lemon juice
  • Salt (to taste)

Steps to Make It

Note: While there are multiple steps, this recipe is broken down into two sections to help you better plan for preparing and cooking the baked fish and garlic aioli.

Prepare the Fish

  1. Gather the ingredients.

    Ingredients for making baked flounder
    ​The Spruce / Ulyana Verbytska
  2. Grease a shallow baking dish. Preheat oven to 325 F/165 C/Gas Mark 3.

    A buttered baking dish
    ​The Spruce / Ulyana Verbytska
  3. Cut the flounder fillets into serving-size portions. 

    Flounder cut into individual servings
    ​The Spruce / Ulyana Verbytska 
  4. Arrange the pieces in the prepared baking dish, and sprinkle fish with salt and the freshly ground black pepper.

    Cut flounder in a baking dish sprinkled with salt and black pepper
    ​The Spruce / Ulyana Verbytska
  5. In a small bowl or measuring cup, combine melted butter, 2 tablespoons lemon juice, and minced onion.

    Melted butter ready to pour or dole out with a spoon
    ​The Spruce / Ulyana Verbytska
  6. Pour the lemon-butter mixture over fish.

    Pouring the butter over the flounder pieces
    ​The Spruce / Ulyana Verbytska
  7. Sprinkle the fish with paprika.

    Paprika is sprinkled over the flounder in the baking dish
    ​The Spruce / Ulyana Verbytska
  8. Bake in the preheated oven for about 20 to 25 minutes or until fish is cooked through and flakes easily with a fork.

    Baked flounder being tested with a fork for flakiness
    ​The Spruce / Ulyana Verbytska
  9. Garnish with chopped parsley, lemon wedges, and serve with garlic aioli (if desired).

    Baked flounder with chopped parsley and lemon wedges
    ​The Spruce / Ulyana Verbytska

Prepare the Garlic Aioli (Optional)

  1. Gather the ingredients.

    Ingredients for making aioli
    ​The Spruce / Ulyana Verbytska
  2. Place the garlic in a small bowl and mash well with a fork. Or mash it using a mortar and pestle.

    Mashing the garlic using a fork
    ​The Spruce / Ulyana Verbytska
  3. Add the mayonnaise, olive oil, and lemon juice and then whisk to blend thoroughly.

    Mixing the mayonnaise, olive oil, and lemon juice with a fork
    ​The Spruce / Ulyana Verbytska
  4. Season with salt.

    Adding salt to the aioli
    ​The Spruce / Ulyana Verbytska
  5. Cover and chill until serving time.

    The aioli is covered in plastic wrap until ready to serve
    ​The Spruce / 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.