Right piece cooked according to instructions (6)
I believe the answer is:
recipe
'instructions' is the definition.
(I've seen this before)
'right piece cooked' is the wordplay.
'right' becomes 'r' (common abbreviation).
'cooked' is an anagram indicator (letters cooked into a new form).
'piece' with letters rearranged gives 'ecipe'.
'r'+'ecipe'='RECIPE'
'according to' acts as a link.
(Other definitions for recipe that I've seen before include "Cooking prescription" , "Set of instructions for preparing a dish" , "Chef's instructions" , "Food method" , "List of ingredients" .)