Japanese Katsuo Tataki: Seared Bonito with Citrus and Aromatics

Ingredients

• 600 g fresh skipjack tuna (katsuo), whole loin block, skin on, landed within 24–48 hours; do not substitute frozen
• 1 tsp fine sea salt, applied before searing; do not salt again at table
• For the aromatics
• 1 medium sweet white onion, halved and sliced paper-thin across the grain, soaked briefly in cold water and drained
• 30 g fresh ginger, peeled and cut into fine julienne
• 2 cloves garlic, finely minced; served beside the fish, not on it, so each diner applies as desired
• 20 g mitsuba (Japanese parsley), stems and leaves roughly separated; substitute flat-leaf parsley only if unavailable
• For the Tosa-style yuzu ponzu
• 60 ml fresh yuzu juice, strained; sudachi or a mixture of lemon and lime is an accepted substitute
• 20 ml ichiban dashi, clean, first-draw; cool before using
• 15 ml light soy sauce (usukuchi), the citrus element must dominate; this is not a standard ponzu ratio
• For the sear
• 2–3 bundles dry rice straw (wara), purchased from a Japanese cooking supply source; must be completely dry; alternatively, a kitchen torch is an acceptable restaurant substitute

Method

1. 1
   Prepare the ice bath. Fill a large bowl with cold water and a generous quantity of ice; set it directly beside the searing station. Mix the yuzu ponzu by combining yuzu juice, ichiban dashi, and light soy in a small bowl; taste — citrus should dominate clearly over soy. Slice the white onion, soak in cold water for five minutes, and drain. Arrange all aromatics and the ponzu on the serving plate before searing begins. The fish will be at the table within minutes of leaving the fire; nothing must wait.
2. 2
   Pat the katsuo loin block dry with kitchen paper. Season lightly and evenly with fine sea salt on all surfaces. Allow to rest uncovered at room temperature for ten minutes so the surface is as dry as possible before it meets the fire. The surface must be dry — moisture will suppress the sear and produce steam rather than the characteristic grassy crust.
3. 3
   This is where the dish lives or dies. Set the katsuo loin on a wire rack positioned directly over a bundle of burning dry straw (wara), or, if using a kitchen torch, hold the flame 3–4 cm from the surface. The straw fire burns at 500–600°C and will sear each surface in 20–30 seconds — no surface may receive more. Rotate the loin through all four sides and, if applicable, both ends. The seared surface turns opaque, pale gold to faintly bronzed, with a faint grassy-smoky aroma; the interior remains wholly raw and translucent. At the first sign of the flesh beginning to cook inward beyond the immediate surface, the fish must come off the heat.
4. 4
   Within five seconds of removing the loin from the fire, plunge it entirely into the ice bath. Hold it submerged for 20–30 seconds until the surface is cold to the touch and firm. Remove and pat thoroughly dry with kitchen paper. Carryover cooking is halted; the interior will be clean, cool, and translucent.
5. 5
   Slice the chilled loin into pieces 7–8 mm thick, cutting perpendicular to the spine with the knife angled slightly. Each slice must show the narrow seared band on the exterior against the translucent, raw interior — this contrast is the visual statement of tataki. Lay slices skin side up on the prepared serving plate over the bed of drained white onion.
6. 6
   Arrange the ginger julienne and mitsuba over and around the fish. Set the minced garlic in a small mound to one side of the plate so each diner applies it at will. Pour the yuzu ponzu into a small jug or pour it carefully around (not over) the slices just before serving. Serve immediately; the dish does not hold.