After a main course, something to follow? (6)
I believe the answer is:
recipe
'follow?' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
I don't understand how the remainder of the clue works.
(Other definitions for recipe that I've seen before include "Food method" , "Directions for cooking a dish" , "Ingredient list" , "Cook's formula" , "Directions for cooking the turkey e.g." .)