What makes the “perfect” french fry is a never-ending debate, and like a chili recipe, everyone has their own preferred methods. But, there are some simple parameters when considering what makes a french fry good: crispiness, and soft interior, and seasoning. A long frying time creates the desired hard exterior but often makes the interior hollow; don’t fry hard enough, and the outside will be soggy. And the nail in the coffin: Salt, which draws moisture to the surface, makes fries soggy. As soon as it’s hit with seasoning, the fry begins to die.
Some people solve these problems by double- or even triple-frying, cooling the fries in between. This method does work, but is often only effective with an industrial fryer and a fast pick-up time. (That, and you still need to work in batches with multiple resting times; even then, the post-salting, soggy fry problem still stands.)
So here’s the true solve, the middle ground between restaurant methods and the perfect salt situation: Pre-cook the fries in brine with an added starch. That way, you’re introducing salt to the interior of the fry, negating the need for post-cook seasoning, while cooking the fry’s interior to a pillowy softness. The added starch also creates a gelatinous coating that will burn off in the cook, leaving ridges of pure crispiness.
Since the interiors are already cooked, just one high-temperature flash fry is needed. It may seem complicated, but when you boil it down (pun intended), it’s just two steps — and the pre-boiled fries can be frozen until later use.