Salchipapas with Fried Sausage Chunks

Salchipapas started on the streets of Lima and now shows up at food trucks from Bogota to South Florida, usually late at night. The trick is scoring each sausage chunk with a shallow cross on the ends so it curls open and crisps in the oil, catching sauce in every split. Fries need two trips into the pot: a low-temperature cook to soften the centers and a hot finish for crunch. Dry the potatoes thoroughly after soaking, or the oil will spit and the fries will steam instead of crisp.