It's sweet when Mel gets a letter from Clara (7)
I believe the answer is:
caramel
'it's sweet' is the definition.
(I know this)
'mel gets a letter from clara' is the wordplay.
I cannot really understand how this works, but
'a' is found in the answer.
'letter' could be 'r' and 'r' is found in the answer.
The remaining letters 'camel' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'when' is the link.
Can you help me to learn more?
(Other definitions for caramel that I've seen before include "It's produced by heating sugar until brown" , "Chewy sweet - burnt sugar" , "Toffee-like sweet" , "Burnt sugar used for flavouring" , "Soft sweet" .)