Ceviche (Cebiche) with Ají Limo and Leche de Tigre

// SUPPLY LIST

// OPERATIONS

1. 1 Put the whole unpeeled sweet potatoes in a 20 cm saucepan, cover with cold water by 3 cm, add the caster sugar, the star anise and a good pinch of salt, and bring to a bare simmer over medium heat — 90–95°C / 194–203°F, the surface just shivering rather than bubbling. Cook 30–40 minutes for pieces of about 200 g, until a thin knife slides to the centre with only the faintest resistance at the core; a rolling boil splits the skins and leaves you with waterlogged mush. Drain, cool for 15 minutes, then peel and cut into 1.5 cm rounds. The sugar and anise are the Peruvian camote glaseado touch, there to push the sweetness up hard enough to stand against the lime.
2. 2 In a second pan of well-salted water at a steady boil, 100°C / 212°F, cook the corn until a kernel is tender with a slight chew — 25–30 minutes for true choclo, but only 5–8 minutes for ordinary supermarket sweetcorn, which is bred tender and goes floury and collapsing if you give it the choclo's time. Lift out and cool, then cut the cob across into 2 cm wheels or strip the kernels off in slabs with a knife.
3. 3 Halve the onion through the root, lay it cut side down and slice it pole to pole into 2 mm feathers (corte pluma) — never across into rings, which gives a curved, watery slice that goes limp the moment acid touches it. Soak the feathers in a bowl of ice water for 10 minutes, until they stiffen and stand up straight and the water clouds faintly, to draw out the sulphurous bite. Drain and pat or spin them completely dry; wet onion thins the leche de tigre and bleeds it cloudy pink.
4. 4 Roll the limes lightly under your palm to loosen the juice, halve them across the equator and squeeze by hand, or in a hinged press with light pressure, stopping the instant the juice stops running freely — wringing them to the last drop presses bitter oils out of the pith and peel, and that is the single most common way home cebiche turns acrid. Never use a spinning electric reamer, which grinds the peel into the juice. Strain through a sieve into a jug to get 300 ml — enough to come up around the fish and still leave a glassful each to drink afterwards — and hold it in the fridge until the moment you need it.
5. 5 Trim any brown bloodline, silverskin and belly fat from the fillet, then cut it into 2 cm cubes with a long sharp knife using single, decisive draw strokes; sawing with a dull blade shreds the surface fibres and those cubes cure into mush. Use only fish you would eat raw — sashimi grade, or fish frozen at -20°C / -4°F for seven days to deal with parasites, because three minutes in lime juice does not make unsafe fish safe. Put the cubes in a glass or steel bowl, cover, and hold in the coldest part of the fridge — or 10 minutes in the freezer — until they are 0–2°C / 32–36°F and feel firm and cold right through. The cure has to start on cold, firm fish.
6. 6 Wearing gloves, slit one ají limo, scrape out the seeds and white ribs and chop it to a fine paste, about 1 tsp; slice the second across into thin rings, seeds and all, and set those aside for garnish. Grate the garlic and the ginger to a smooth paste on a microplane — anything coarser leaves hot fibrous threads floating in the leche. Kion and garlic are the Lima touch, the Nikkei and Chinese end of the tradition; the cebiche of Piura and Lambayeque is deliberately purist and leaves both out, so for the northern version skip them and let fish, lime, salt and ají carry the plate alone.
7. 7 Tip the fish into a chilled non-reactive bowl — glass, ceramic or stainless steel, never aluminium or bare copper, which react with the acid and leave a tinny, metallic taste — add the 2 tsp fine salt, the ají paste, and the garlic and ginger if you are using them, and turn it over gently with a spoon for 30 seconds. Let it sit for 1 minute, until the cut surfaces look faintly tacky rather than wet. Salting before the lime seasons the flesh from within and firms the surface; salt stirred in after the acid just sits on top and the dish tastes flat and sharp at the same time.
8. 8 Pour the cold lime juice over the fish so it comes about three-quarters of the way up the cubes, not so far that they float, drop in 2 of the ice cubes and stir once. Cure for 2 to 3 minutes only, watching for the cubes to go opaque white about 2 mm deep while the centre stays translucent and glossy when you cut one in half. Do not revive the colonial hours-long marinade: past roughly 10 minutes the acid drives the water out of the muscle and the fish turns dry, chalky and cotton-woolly.
9. 9 Fish out the ice cubes, add the drained onion and the chopped coriander, and fold everything over three or four times — no more, or the onion bleeds pink into the leche and goes floppy. Taste the liquid off a spoon: it should land sour, then salty, then hot, in that order, and pull you back for a second spoonful. Correct with a pinch of salt or a squeeze of lime; if it is screamingly sharp, a small pinch of the caster sugar rounds it off without being detectable.
10. 10 Line four chilled shallow bowls with a lettuce leaf, spoon the fish and all of its leche de tigre over — the liquid is half the dish, so be generous — and lay three or four rounds of camote and two wheels of choclo alongside the fish rather than on top of it, so the sweetness stays a separate bite that resets the palate. The camote and choclo must be cool or barely warm, never hot; heat on the plate carries on cooking the fish while it sits.
11. 11 Scatter the ají limo rings and a good handful of cancha over each bowl and get them to the table within two minutes of the lime going in. Cebiche does not rest and does not keep: it goes on curing in the bowl, and a plate that waits ten minutes on the pass is a different and much worse dish. There are no leftovers — anything cured and then refrigerated overnight should be thrown away.
12. 12 Pour whatever leche de tigre is left in the mixing bowl into small chilled glasses and serve it alongside, with cold Cusqueña or Pilsen Callao, or a chilcano de pisco. In Piura and Lambayeque a spoonful of boiled zarandaja beans, a round of boiled yuca and a scatter of chifles (fried plantain crisps) go on the plate as well; in Lima, camote, choclo and cancha are all it has ever needed.

// CLASSIFICATIONS