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5 from 2 votes
Simmered flounder on a plate.
Simmered Flounder (Karei no Nitsuke)
Prep Time
5 mins
Cook Time
10 mins
Total Time
15 mins

A classic simmered seafood dish, Simmered Flounder is so simple. Cooked in a sweet and salty sauce with ginger, Simmered Flounder goes so well with rice. The sauce only penetrates the surface of the flesh and you can enjoy the flavour of the moist and plump flounder.

Don't forget to see the section 'MEAL IDEAS' below the recipe card! It gives you a list of dishes that I have already posted and this recipe so you can make up a complete meal. I hope it is of help to you.

Recipe Type: Main
Cuisine: Japanese
Keyword: flounder, flounder recipe, Japanese fish recipe, nitsuke, simmered fish
Serves: 2
Author: Yumiko
Ingredients (tbsp=15ml, cup=250ml)
  • 1 whole flounder (about 350g / 0.8lb, note 1)
  • 2 stems shallots/scallions cut into 5cm / 2” long pieces
  • 1 tbsp ginger thinly sliced
Simmering Sauce
  • 4 tbsp water
  • 4 tbsp cooking sake
  • 1 tbsp mirin
  • 2 tbsp soy sauce
  • 2 tbsp sugar
  • 1 tbsp ginger finely julienned (note 2)
  1. If the flounder is not cleaned, remove the guts and scales. Cut the head and the tail off and discard. Cut the flounder in half, perpendicular to the back bone (note 1).

  2. Make a cross incision on the right side of the fish (brown side) where the flesh is the thickest (see the photo in post). If you are using narrow strips of flounder cutlet, incision is not required.
  3. Add all the Simmering Sauce ingredients to a shallow saucepan or a frying pan that can just fit the flounder pieces without overlapping.

  4. Add the sliced ginger and bring it to a boil.
  5. Put the flounder pieces in the sauce without overlapping, then place the shallots around the flounder pieces.

  6. Place a drop lid (otoshi buta) on, reduce the heat to medium to medium low and cook for about 5 minutes.

  7. Remove the drop lid. Using a spoon, scoop the sauce and pour over the fish while continuing to cook for another few minutes. The sauce will become a bit thicker.
  8. Turn the heat off and transfer the fish to individual plates. Place the cooked shallots to the side of the fish and the julienned ginger on the centre of the fish.

Recipe Notes

1. Each flounder piece weighed about 150g / 5.3oz after preparing.

If your flounder is very large, cut the flounder into narrow strips, perpendicular to the backbone. If your flounder is very small, you can serve a whole fish per person.

If you want to, you can use a fillet without bones. In this case, place the fillets with skin side up.

2. If your julienned ginger pieces are limp, place them in ice water for a while. They should become stiff. Stiff julienned ginger is called ‘harishōga’ (針生姜), which translates to needle ginger. They look attractive when piled high and placed on the food.

3. Simmered Flounder can keep 1-2 days in the fridge. The flesh will absorb the sauce flavour more overnight and you might find that the fish has a bit stronger flavour.

You can also freeze Simmered Flounder for 1 month. Make sure that the flounder is put in the sauce, then frozen so that the flesh does not dry. Thaw in the fridge before heating up.

4. Nutrition per serving. It assumed 50% of the sauce is consumed but in reality, you don't drink the sauce served on the plate so the sodium and sugar would be lower.

serving: 244g calories: 196kcal fat: 3g (5%) saturated fat: 0.7g (3%) trans fat: 0.0g polyunsaturated fat: 0.6g monounsaturated fat: 0.8g cholesterol: 68mg (23%) sodium: 890mg (37%) potassium: 439mg (13%) carbohydrates: 17g (6%) dietary fibre: 1.5g (6%) sugar: 11g protein: 20g vitamin a: 1% vitamin c: 6% calcium: 4% iron: 5.2%