Personally I think the main thing is not to over crowed the pan with too much potato. Yes I too fry the French fries twice, but if there is too much potato no matter how many times you fry them they will not be good. You can fry them at once and if there is enough room and you have patients not too burn them and not too stir them too many times, just let them be, they will come out good, even if you start frying with the lid on, which allows potato to steam and cook faster after you take the lid off you need to let them fry nicely.