The other day I washed and dried and rubbed with olive oil a bunch of Yukon Gold potatoes. I baked them jut until done. These potatoes never go 'mealy like Idaho/Russets.
I had a few left over so I refrigerated them. Last night I'm poaching a piece of fresh Spring salmon. Why not 'fish and chips'? So I cut the cold Yukons into 1/4" size 'fries' and dredged in some tapioca flour shaking off the excess. The way I now deep fry 'fries' is to put a few cups of room temperature canola oil or whatever in a deep sauce pan add the room temperature fries. Bring the oil/fries to a rolling boil. I do not 'play' with the fries while they are frying. When I'm happy with the color of the fries I remove them with a spider and place on p towels. The fries never stick together bc of the tapioca flour. The result was amazing! Even after the left over dries had cooled to room temperature after we'd eaten all we wanted they were STILL crispy! This morning out of the fridge they are still crispy! Very nice texture inside but still crispy on the surface. I think this is the way I'll do fries from now on. I think the result was a combination of the tapioca flour of course but also using pre baked Yukon Gold potatoes is a factor.