quicko: what all

I was recently called out for using "what all" at the beginning of a question -- "What all comes on the burger?" -- or some such syntactical nightmare, according to my friends.  I saw nothing wrong with my construction (I am an English teacher!  Of course it was correct!), but the Australians around me let loose with an array of unpleasantries regarding my use of the English language.  I suppose, upon reflection, it is not of the highest possible register, but, really, is the highest possible register strictly necessary when, say, ordering a burger?  All in all, I stand by what all.