I read somewhere that the original latkes may have been fried cheese until they moved into the more northerly parts of Europe, where olive oil was scarce and lard was more common. Since there is a Jewish rule not to mix meat and dairy, the cheese was abandoned for cakes made from root vegetables. I also add some grated cheese at time to my latkes, and do make fried cheese as well (although usually it has enough fat to fry itself and then some, in the case of a hard cheese).