Karei no Nitsuke Simmered Flounder in Sake and Soy

Ingredients

• 4 karei (flounder or similar flatfish), whole, cleaned, fresh preferred; scored on both sides through skin
• 200 ml sake
• 100 ml mirin
• 100 ml soy sauce
• 200 ml water, or dashi
• 30 g fresh ginger, peeled and julienned
• 2 negi (green onion / Japanese long onion), cut into 5 cm lengths

Method

1. 1
   Shimo-furi: bring a large volume of water to a rolling boil. Submerge each fish briefly — no more than a few seconds — until the surface whitens and turns opaque. Lift out immediately and plunge into cold water. The surface should show an even, frost-like whitening with no raw patches remaining. Pat dry.
2. 2
   Combine sake, mirin, soy sauce, and water (or dashi) in a wide, shallow pan of sufficient diameter to hold the fish in a single layer. Bring the liquid to a simmer over medium heat. The surface should show a steady, gentle movement across its full width — not a hard boil.
3. 3
   Add the julienned ginger to the simmering liquid. Lower the fish into the pan. The liquid must already be simmering before the fish enters it; cold-liquid entry is the principal fault of a failed nitsuke. Settle the fish in a single layer without overlapping.
4. 4
   Place an otoshibuta — a drop lid cut just smaller than the interior of the pan, whether wooden, aluminium foil, or baking parchment, pierced at the centre — directly onto the surface of the liquid and fish. This is the step on which the dish lives or dies: the otoshibuta simultaneously circulates the simmering liquid evenly over every surface of the fish, prevents the fish from shifting and breaking, and controls the rate of evaporation for proper reduction. Without it, a standard lid traps steam and the liquid dilutes rather than concentrates; no lid at all leaves the exposed fish dry and unglazed.
5. 5
   Simmer with the otoshibuta in place, periodically lifting it to spoon cooking liquid from the sides of the pan up over any exposed fish surface. Continue until the fish is just cooked through — the flesh at the thickest point yields cleanly when pressed and shows no translucency at the bone.
6. 6
   Add the negi in the final minute of cooking. Remove the fish carefully to a warm serving plate. If the cooking liquid has not yet reached a glossy, lightly viscous consistency, return the pan to the heat and reduce briefly without the fish. The finished sauce should coat the back of a spoon with a lacquered sheen.
7. 7
   Spoon the reduced sauce over the plated fish. The surface of the fish should show an even, glossy lacquer. Taste the sauce: sake and mirin should be clearly present alongside the soy — the balance is forward in sweetness and aromatic warmth, not simply salty.