Turnover-like pud is done unconventionally, adding whiskey (6,4)
I believe the answer is:
upside down
I'm afraid I can't even guess how this answer relates to the clue.
Can you help me to learn more?
(Other definitions for upside down that I've seen before include "in a crazy way" , "kind of cake" , "at sixes and sevens" , "in a chaotic manner" , "Inverted" .)