Leche de Tigre

Pour the strained lime juice and cold fish stock into a bowl. Add a handful of ice and stir until the mixture is thoroughly chilled — you want it between 2 and 4C / 36–40F before blending. This is non-negotiable: leche de tigre is blended cold, served cold, and the colder it stays during preparation, the brighter, cleaner, and more vivid the citrus will taste. Cold also prevents the fish protein from cooking during the blending step, keeping the finished liquid clean and translucent rather than cloudy and cooked-tasting. Remove the ice before blending.

Place the chilled citrus base in a blender. Add the raw fish scraps, ají amarillo paste, sliced ginger, celery, garlic, cilantro leaves and stems, red onion, and salt. Blend at high speed for 45 seconds — no longer. Over-blending oxidizes the cilantro and warms the mixture from friction, both of which flatten the flavor. The goal is a forceful but brief blitz that breaks down all the solids into the liquid without turning the whole thing into a warm, foamy soup. The fish provides body and a subtle creaminess as its proteins emulsify into the acid — this is the 'milk' of tiger's milk.

Set a fine-mesh sieve over a bowl resting in an ice bath. Pour the blended leche through the sieve and use the back of a ladle or spoon to gently press and extract as much liquid from the solids as possible. Do not force — pressing too hard pushes through the fibrous celery and ginger, which turns the liquid bitter and grassy. You want to extract the flavored liquid while leaving the coarser solids behind. Discard the pressed solids. The strained liquid should be very cold, almost completely clear with just the faintest milky opalescence, and searingly vivid in smell.

Taste the strained leche de tigre. Adjust salt. If the citrus is overwhelming, add a small amount of additional fish stock to soften the acid edge without losing the vivacity. If it lacks heat, whisk in a touch more ají amarillo paste. Serve immediately in two ways: as a sauce poured over ceviche (where it becomes the curing and serving liquid simultaneously), or as a shot in a small chilled glass topped with cancha (toasted corn kernels) — the traditional way to start a ceviche meal. Leche de tigre does not keep well; the aromatics fade and the acid continues to dull within an hour. Make and use immediately.