Green’s Dictionary of Slang

raspberries! excl.

also razzberry
[raspberry n. (1)]

(US) an excl. used to express disbelief or defiance.

A. Baer Metropolitan Game Laws 4 Sept. [synd. col.] But who protects the pedestrian? And echo answers razzberries.
[US]Wash. Post 25 Jan. SM7: Jargon of the Juveniles Daughter Raspberries.
[UK]R. Carr Rampant Age 20: ‘Aw, razzberries – ’ began Paul, but the heavy voice of his father drowned out his protest.
[US]L. Hughes Laughing to Keep from Crying 135: I gave her the polite raspberries – after I shut the door.
[US](con. 1916) G. Swarthout Tin Lizzie Troop (1978) 136: ‘Raspberries!’ howled Darlington.