sweet potato – boiled until tender, sliced (for serving)
Peruvian corn (choclo) – boiled and cut into rounds (for serving)
12 each limes – juiced (freshly squeezed)
1 cups red onion – thinly sliced, rinsed and drained
1 pounds firm white fish – skinless, pin bones removed, cut into 0.75-inch cubes, well-chilled
1 each fresh hot chili pepper – ajà limo or ajà amarillo preferred, finely sliced
1.5 teaspoons kosher salt
0.25 cups cilantro – finely chopped
lettuce leaves – chilled (for serving)
Instructions
Place the sweet potato and Peruvian corn (choclo) in separate pots, cover with water, bring to a boil, and cook until the sweet potato is tender when pierced, 20–30 minutes, and the corn kernels are tender, 15–20 minutes. Drain and cool completely; slice the tuber and cut the cob into rounds for serving.
Roll the limes on the counter, then juice and strain to yield about 1 cup; chill the juice.
Thinly slice the red onion, rinse under very cold water, and drain well; keep chilled.
In a chilled nonreactive bowl, add the firm white fish, the fresh hot chili pepper, and the kosher salt; toss gently to distribute.
Pour the chilled lime juice over the bowl, turning to coat evenly; let stand 8–12 minutes, stirring once or twice, until the edges of the cubes look opaque while the centers remain slightly translucent.
Finely chop the cilantro and fold it, along with the sliced onion, into the ceviche; taste and adjust seasoning.
Line plates with lettuce leaves and spoon on the ceviche with a little of its milky marinade; serve alongside the prepared sweet potato and corn.