Somewhat sweet, is it? (1,6)

I believe the answer is:
a trifle
'somewhat' is the definition.
(I've seen this in another clue)
'sweet is it?' is the wordplay.
I cannot quite see how this works, but
'sweet' could be 'trifle' (trifle is a kind of sweet) and 'trifle' is present in the answer.
A single letter 'a' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for a trifle that I've seen before include "somewhat" , "Slightly" .)
