Dessert served a la mode (3)
I believe the answer is:
pie
'dessert served a la mode' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for pie that I've seen before include "Pecan or blueberry dish?" , "Pastry-topped dish" , "See 6" , "Covered flan" , "Anna's constituent" .)