Cake is warmer at home (6)
I believe the answer is:
muffin
'cake' is the definition.
(I've seen this before)
'warmer at home' is the wordplay.
'warmer' becomes 'muff' (I can't justify this - if you can you should give a lot more credence to this answer).
'at home' becomes 'in' ('I'm in' can mean 'I'm at home').
'muff'+'in'='MUFFIN'
'is' is the link.
Can you help me to learn more?
(Other definitions for muffin that I've seen before include "Yeast roll for toasting" , "Small cake" , "Round raised cake, often split and toasted" , "Toasted, spongy bread roll" , "Have IMF fun with the cake" .)