Seared Tuna with Sesame Crust and Asian Slaw

Ingredients

• 4 tuna steaks, about 3cm thick (approx. 180g each)
• 1 tbsp toasted sesame oil
• 3 tbsp black sesame seeds
• 3 tbsp white sesame seeds
• 1 tbsp neutral oil, such as sunflower or groundnut
• 2 tbsp rice wine vinegar
• 15g fresh root ginger, finely grated
• 1 garlic clove, finely grated
• 3 tbsp soy sauce
• 1 tsp honey
• 1 tbsp toasted sesame oil
• 1 lime, juiced
• 300g white cabbage, very finely shredded
• 2 carrots, peeled and julienned or coarsely grated
• 8 radishes, thinly sliced into rounds
• 4 spring onions, thinly sliced on the diagonal
• 20g fresh coriander, roughly torn
• 30g pickled ginger, to serve
• chilli oil, to drizzle, to serve
• 1 lime, cut into wedges, to serve

Method

1. Start with the dressing. Whisk the soy sauce, rice wine vinegar, sesame oil, grated ginger, grated garlic, honey and lime juice together in a small bowl. The garlic goes in raw here, so grate it fine — and trust the lime juice and vinegar to mellow its edge as it sits. Taste: it should land sharp, savoury and just lightly sweet. Most of the salt comes from the soy, so add a pinch more only if it needs lifting.
2. Tip the shredded cabbage, carrot, radishes and spring onions into a large bowl. Pour over two-thirds of the dressing and toss thoroughly with your hands so every strand is coated. Leave for at least 10 minutes — the vegetables soften slightly, drink in the dressing, and lose that raw squeak.
3. Mix the black and white sesame seeds together on a flat plate. Pat the tuna steaks dry with kitchen paper — wet fish steams instead of searing, and the seeds won't stick to a damp surface. Brush each steak all over with the toasted sesame oil, then season generously with salt and pepper on both sides.
4. Press each tuna steak firmly into the sesame seeds, turning and pressing on the edges too so you build a thick, even crust on every face.
5. Heat the neutral oil in a stainless steel or cast iron frying pan over a very high heat until it shimmers and is just starting to smoke. Don't crowd the pan — work in two batches if your pan won't comfortably hold all four steaks in a single layer with space between them. Crowded steaks throw out steam and the crust goes soft instead of crisp.
6. Lay the tuna in carefully and sear for 90 seconds on each side until the sesame crust is deep golden and smells nutty and toasted, but the centre stays rare and cool. Stand the steaks on their thin edges briefly too, about 20 seconds each, to set the crust all the way round.
7. Lift the tuna onto a board and rest for 1 minute. Slice each steak thickly against the grain — you're looking for a thin band of seared, seedy crust framing a vivid pink middle.
8. Taste the slaw one more time and adjust the seasoning — a little more salt, another squeeze of lime if it needs sharpening. Fold the torn coriander through at the last second so it stays bright.
9. Pile the slaw onto a large platter or divide between four plates. Lay the sliced tuna over the top, spoon the remaining dressing across the fish, and tuck the pickled ginger alongside. Drizzle with chilli oil and finish with the lime wedges for squeezing at the table.