Sausage put aside - large and extremely oily (7)
I believe the answer is:
saveloy
'sausage' is the definition.
(I know that Saveloy is a type of sausage)
'put aside large and extremely oily' is the wordplay.
'put aside' becomes 'save' (I've seen this in another clue).
'large' becomes 'L' (eg in clothes sizes).
'and' is a charade indicator (letters next to each other).
'extremely' suggests removing the centre (letters on the extremes of the word are used).
'oily' with its centre taken out is 'oy'.
'save'+'l'+'oy'='SAVELOY'
(Other definitions for saveloy that I've seen before include "Highly seasoned pork sausage - love, say (anag)" , "Type of sausage" , "One using brains originally" , "Big sausage" , "Spicy sausage" .)