Goes towards quiche, having early advantage (4,5)
I believe the answer is:
head start
'early advantage' is the definition.
(I've seen this in another clue)
'goes towards quiche' is the wordplay.
'goes' becomes 'heads' (I can't justify this - if you can you should give a lot more credence to this answer).
'towards' means one lot of letters go next to another (I've seen this in other clues).
'quiche' becomes 'tart'.
'heads'+'tart'='HEAD START'
'having' acts as a link.
Can you help me to learn more?
(Other definitions for head start that I've seen before include "It improves the chances of success!" , "Boost?" , "advantage, initially" , "An early advantage for the star ad" , "Substantial initial advantage" .)