Green’s Dictionary of Slang

a general excl. of intensification, i.e. I certainly did! usu. in answer to a question, also with other personal pronouns or ‘anyone’.

1960		A. Seymour One Day of the Year (1977) II iii: mum: You’re goin’ to put that in a paper? hughie: Are we ever?
1972		C.E. Palmer Wooing of Beppo Tate 120: And did I ever go! Did I ever burn up that turf!
1996		Penguin Bk of More Aus. Jokes 207: ‘Did you have a party here last night?’ ‘Christ,’ groaned the woman, ‘did we ever.’.