I creep over to produce formula (6)
I believe the answer is:
recipe
'formula' is the definition.
('recipe' can be a synonym of 'formula')
'i creep over to produce' is the wordplay.
'over' says to put letters next to each other.
'to produce' indicates anagramming the letters.
'i' put after 'creep' is 'creepi'.
'creepi' anagrammed gives 'RECIPE'.
(Other definitions for recipe that I've seen before include "Cooking prescription" , "Instructions on how to cook" , "Kitchen instructions" , "Directions for making food etc" , "Directions for preparing food, etc" .)