Like good cold jelly? (5)
I believe the answer is:
aspic
'jelly?' is the definition.
(aspic is a kind of jelly)
'like good cold' is the wordplay.
'like' becomes 'as'.
'good' becomes 'pi' (I've seen this in other clues).
'cold' becomes 'c' (eg on taps).
'as'+'pi'+'c'='ASPIC'
(Other definitions for aspic that I've seen before include "Jelly made with fish or meat stock" , "garnish" , "Jelly based on fish or meat stock" , "that's clear?" , "Savoury jelly for meat or vegetable" .)