Potatoes cut into thin strips and fried in five minutes, salted after they come out and eaten with pink sauce. Three ingredients, and drying the potato is what makes them crisp.
Dry the potatoes before they go in. This is the single thing that separates crisp fries from limp ones and the recipe never mentions it: cut potato is wet, and water hitting hot oil turns to steam, which is why they spit and why the surface never crisps. Pat them dry with a tea towel and it changes the result entirely. Rinsing them first helps too, since it takes off the loose starch that makes them stick together, but they have to be dried afterwards. Do not crowd the pan. Every potato added drops the temperature of the oil, and oil that has cooled is absorbed rather than driven off, which gives greasy fries. Two batches beat one crowded one. Salt after, never before. Salt on raw potato draws water to the surface, which is exactly what you have just spent time removing, and salt in hot oil spits. Pink sauce is the Colombian way: mayonnaise and tomato sauce mixed in roughly equal parts.