Greedy guts swallowing last of bacon on soggy ground bread once (7)
I believe the answer is:
pfennig
'bread once' is the definition.
(former monetary unit of Germany)
'greedy guts swallowing last of bacon on soggy ground' is the wordplay.
'greedy guts' becomes 'pig' (both can mean a greedy person).
'swallowing' means one lot of letters goes inside another.
'last of' suggests the final letters.
'on' means one lot of letters goes inside another.
'soggy ground' becomes 'fen' (I've seen this in another clue).
The final letter of 'bacon' is 'n'.
'n' going within 'fen' is 'fenn'.
'pig' enclosing 'fenn' is 'PFENNIG'.
(Other definitions for pfennig that I've seen before include "Old German monetary unit" , "Hundredth of an old Deutschmark" , "Old German currency unit" , "Former German coin" , "Approximately two point two zero five pounds" .)