Last bit of food eaten by dogs -- soft stuff (5)
I believe the answer is:
curds
'soft stuff' is the definition.
'last bit of food eaten by dogs' is the wordplay.
'last bit of' indicates one should take the final letters.
'eaten by' indicates putting letters inside.
'dogs' becomes 'curs' (cur is a kind of dog).
The last letter of 'food' is 'd'.
'd' inserted within 'curs' is 'CURDS'.
(Other definitions for curds that I've seen before include "Coagulated milk, used to make cheese" , "Basis for making cheese" , "Solids in coagulated milk" , "Golfing attendant" , "Coagulated milk particles" .)