This quick oven baked flounder recipe stems from the Baltic Sea and is very popular in the North-East of Germany and the Scandinavian countries. The mustard sauce in which the fish fillets are baked in is super creamy.
The addition of onions and pickles make this dish an amazing experience. You can whip this recipe up in less than 10 minutes active working time but your family will think you might stood an hour in the kitchen.
One stereotype of German cuisine is that fish is basically not existent on the menu, but Germany has a huge variety of tasty fish dishes that stem mostly from the coasts of Germany of the North Sea and the Baltic Sea.
One of my favorite German street food is a Herringsbrötchen (herring roll), a simple snack with a crusty roll, pickled herring and finely chopped onion rings.
Another amazing German fish dish are Matjes nach Hausfrauen Art, tender herring fillets in an amazing creamy sauce which are often served with crispy fried potatoes.
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Ingredients
The dish can be made with a few simple ingredients but tastes like a gourmet dish from a fancy restaurant.
- 3 pounds flounder fillets without skin
- ½ lemon
- salt & pepper
- 1 tbsp. butter
- 1 onion
- 20 cornichon pickles or 6 large dill gherkins
- 1 cup heavy cream
- 1 cup sour cream
- 6 tbsp. mustard
- 1 tsp. coarse black pepper
See recipe card for quantities.
Instructions
This dish will be prepped in less than 10 minutes. It´s best to start with preheating the oven to 350°F..
In the meantime, clean your fish and squeeze the juice of half of a lemon over the fish fillets.
Then butter a casserole dish and place the fish fillets in one layer into the pan. You need perhaps two casserole dishes, depending on the size of your fish fillets and your casserole dish.
Then salt and pepper the fish fillets on both sides.
Mix sour cream, heavy cream and mustard in a small mixing bowl to a smooth consistency.
Finely chop onion and the cornichon pickles and add them with the coarse black pepper to the mustard sauce.
pour your mixture over the fish fillets and spread it out evenly.
Substitutions
This dish is also suited for low carb and ketogenic diets. Here are some substitutions if you would like to lower the calorie count or adjust to your own taste.
- Heavy Cream - instead of heavy cream you can use half and half.
- Cornichon Pickles - if you can´t find cornichon pickles, use bread and butter pickles or dill gherkins. If you are on a low carb diet make sure that your pickles don´t have added sugar.
- Flounder Fillets - the dish also works well with other fish varieties i.e. Tilapia, Walleye or Swai.
Variations
Try these variations to make this dish more to your liking.
- Spicy - add banana pepper rings instead of pickles to the sauce.
- Deluxe - Use king prawns instead of fish fillet. It is best to butterfly the prawns before placing them into the casserole dish.
- Garlic - add a teaspoon of garlic paste to the sauce.
See this recipe for homemade garlic paste on my website! It is easy to prep, way cheaper than store bought garlic paste and tastes like you added freshly chopped garlic to the dish.
Equipment
I use my cheap Ikea glass casserole dishes for this recipe, but you can use stoneware for this dish too.
Storage
This dish can be re-heated but is not the best for freezing or meal prep. But you can make the sauce ahead of time and allow the fish fillets to defrost in the morning. This way your dish is ready to go into the oven in just a couple of minutes.
Top Tip
Make sure to butter the sides of the dish too, as this will make clean up so much easier.
Serve with
Serve with a German Salzkartoffeln (boiled potatoes), rice or mashed potatoes and a vegetable side dish. My favorite veggie sides are broccoli or this peas & carrots dish with buttery bread crumbs.
Recipe
Quick Flounder Fish Fillets In Creamy Mustard Sauce
Equipment
- 1-2 Casserole Dish(es)
Ingredients
- 3 pounds flounder fillets without skin
- ½ lemon
- salt & pepper to taste
- 1 tbsp. butter
- 1 onion
- 20 cornichon pickles or 6 large dill gherkins
- 1 cup heavy cream
- 1 cup sour cream
- 6 tbsp. mustard
- 1 tsp. coarse black pepper
Instructions
- Preheat oven to 350°F.
- In the meantime, clean flounder fillets and squeeze the juice of half of a lemon over the fish fillets.
- Butter a casserole dish and place the fish fillets in one layer into the pan.
- Salt and pepper on both sides.
- Add sour cream and heavy cream to a small bowl and mix with mustard.
- Finely chop onion and cornichon pickles and add with the coarse black pepper to the bowl.
- Mix well and pour over the fish fillets.
- Bake for about 15-20 minutes.
Notes
Nutrition
Food Safety
- Wash hands after handling raw fish
- Don't re-freeze thawed fish.
See more guidelines at USDA.gov.
Frequently Asked Questions
Flounder is a very delicate fish. Cook the fish fillets to a temperature between 140 °F (60 °C) to 145 °F (63 °C)
Thin sided fish like flounder can get mushy if it is watered for too long. The same can happen if you drizzle the fillets with lemon juice and let them marinate for too.
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