I know I'm a bit late here, but I do have an alternative to frying twice. If you don't want to fry twice, you can also boil the french fries in water that has one or two tablespoons of vinegar or lemon juice for about 15 minutes. You have to allow the fries to cool down after the boiling, at least until the steam is no longer present, before frying.
This is because the purpose of the first time cooking is to stimulate gelatinization and water loss. The fries are able to crisp due to the absence of water in the outer layer of the fries. The acid from the vinegar protects the starch from reacting with the boiling water. If you leave out the vinegar/lemon juice, the end result will not be the same.
Personally, I like this approach because it's less messy than frying twice and you can leave the pot unattended.