... like the one I've sometimes seen for french fries? It calls for an initial frying in low-temperature oil essentially to cook the fries, then a second frying in high-temperature oil to re-heat and brown them. It sounds like you're suggesting this might work for the celery root.
i actually just saw an episode of "molto mario" where mario was frying celery. it was a favorite of his uncle's. he dipped the celery pieces in egg and flour and fried in olive oil. i was channel surfing so i didn't see what seasoning he added at the end.
I've used the celeriac crisps on various occasions and they go very well with game dishes. You can also cook it and make a puree which is nice and sweet.
To make the crisps you just slice it on a mandoline as thin as you can. Then wash it in cold water and dry with a towel as best as possible. Fry in fryer (same temperature as chips) for about 2 to 3 minutes. Don't forget to season them when you take them out.
Brown sugar, celery and celery root (celeriac) are two different things. Celery root is a starchy root, more along the lines of a potato. It has a hard, brown, hairy skin that must be peeled and a white (off-white) starchy interior. It it used more like a root vegetable such as potato, turnip, parsnip than like celery.