Dry-aged Bluefin Otoro Recipe

Trim and portion

Inspect the otoro and trim away any loose connective tissue or bloodline using a very sharp knife. Portion the loin into a single whole piece about 1–1.25 lb if not already portioned; keep the surface dry with paper towels.

Make curing mix

Combine kosher salt, granulated sugar and ground white pepper in a small bowl and mix thoroughly to create an even cure. The salt/sugar mix draws moisture to concentrate flavor and firm the flesh—use the measured amounts to avoid over-salting the prized fat.

Apply cure

On a clean work surface, spread a layer of plastic wrap large enough to wrap the fish. Sprinkle a thin, even layer (about one-third of the mixture) of the cure on the plastic wrap where the fish will sit. Place the otoro, skin-side down if skin is present, onto the cure bed. Massage a light, even coating (about one-third of the cure) over the top exposed surface of the fish. Reserve the remaining cure—do not pack the fish heavily; you want a gentle cure to draw just enough moisture over several days.

Wrap and set on rack

Loosely wrap the fish with the plastic wrap so air can still circulate slightly but the fish is protected from direct fridge odors. Place the wrapped fish on a wire rack over a tray to catch any drip. Put the tray in the coldest part of the refrigerator (34–38°F / 1–3°C).

Age

Age the otoro for 48–72 hours for a modest concentration and texture change, or up to 5–7 days for a more pronounced dry-aged effect. Check every 24 hours: unwrap, blot any accumulated liquid with paper towels, reapply a very light pinch of the reserved cure only if surface appears too wet, rewrap and return to fridge. Do not let it dry out completely—aim for a slightly tacky, firmer exterior while the interior remains silky.

Rinse and rest

When the desired age is reached, unwrap and gently rinse the cure off under very cold running water or wipe thoroughly with a damp cloth to remove excess salt and sugar. Pat the fish dry with paper towels. Let rest on a rack in the fridge, uncovered, for 30–60 minutes to allow the surface to form a slight pellicle and further concentrate flavor.

Slice

Using a very sharp, long sashimi knife, slice the otoro into thin sashimi slices (about 1/8–1/4 inch / 3–6 mm) against the grain at a slight angle to showcase the marbling. For nigiri, cut slightly thicker slices (about 1/4 inch / 6 mm). Wipe the knife between cuts to keep clean slices.

Dress and plate

Arrange slices on chilled plates. Lightly brush or dot each piece with a scant amount of neutral oil or smoked olive oil (about 1/4 tsp per slice total across serving) to lift the fat flavors. Sprinkle a small pinch of flaky sea salt over each slice to enhance the taste. Add a few microgreens or chive blossoms and a few drops or a slice of citrus (yuzu or lemon) if using—avoid heavy condiments so the otoro's extra-fatty character remains the star.

Serving notes

Serve immediately at near-sashimi temperature. Recommend 4–6 sashimi slices per person as a rich tasting portion. Leftovers: keep tightly wrapped and refrigerated and consume within 24 hours for best quality; do not refreeze.

Sanitize all surfaces and knives before and after handling raw fish. Maintain refrigerator temperature at 34–38°F (1–3°C) throughout the cure/dry-aging period. Because this is raw fish preparation, use only sashimi-grade tuna sourced from a reputable supplier and follow local food-safety guidance.