Dessert from flipping United States — I ruin it (8)
I believe the answer is:
tiramisu
'dessert' is the definition.
(I've seen this before)
'flipping united states i ruin it' is the wordplay.
'flipping' says the letters should be written in reverse.
'united states' becomes 'us' (abbreviation for the United States).
'ruin' becomes 'mar' (I've seen this before).
'us'+'i'+'mar'+'it'='usimarit'
'usimarit' back-to-front is 'TIRAMISU'.
'from' acts as a link.
(Other definitions for tiramisu that I've seen before include "Greek dessert" , "Italian sponge pudding" , "Rich Italian dessert" , "It. dessert, literally pick me up" , "Italian dessert with coffee and liqueur" .)