One sheep is eaten by you, French dish that's spongy (8)
I believe the answer is:
tiramisu
'dish that's spongy' is the definition.
'one sheep is eaten by you french' is the wordplay.
'one' becomes 'i' (Roman numeral).
'sheep' becomes 'ram' (male sheep).
'eaten by' indicates putting letters inside.
'you french' becomes 'tu' ('you' in French).
'i'+'ram'+'is'='iramis'
'iramis' going inside 'tu' is 'TIRAMISU'.
(Other definitions for tiramisu that I've seen before include "It. dessert, literally pick me up" , "for which damp sponge is needed" , "Sweet" , "Dessert -- is it arum? (anag)" , "Greek dessert" .)