Trifle that’s obviously yummy, first of all (3)
I believe the answer is:
toy
'trifle' is the definition.
(I've seen this before)
'that's obviously yummy first of all' is the wordplay.
'first of all' suggests taking the first letters.
The initial letters of 'that obviously yummy' is 'TOY'.
(Other definitions for toy that I've seen before include "Teddy or Dolly" , "Doll or teddy, say" , "Trifle or dally with" , "Trifle with plaything?" , "Child's amusement" .)