Change tack in coastal area and get a snack?
I believe the answer is:
shortcake
'a snack?' is the definition.
'change tack in coastal area' is the wordplay.
'change' is an anagram indicator.
'in' indicates putting letters inside.
'coastal area' becomes 'shore' (I've seen this before).
'tack' with letters rearranged gives 'tcak'.
'tcak' put into 'shore' is 'SHORTCAKE'.
'and get' acts as a link.
(Other definitions for shortcake that I've seen before include "Rich biscuit; American dessert" , "Dessert from America" , "Crisp, rich, crumbly, buttery biscuit" , "pastry?" , "Sweet biscuit - rat chokes (anag)" .)