Strains to produce puzzles (7)
I believe the answer is:
riddles
This clue is a double definition.
'strains' is the first definition.
(riddling is a kind of straining)
'puzzles' is the second definition.
(riddling is a kind of puzzling)
'to produce' acts as a link.
(Other definitions for riddles that I've seen before include "problems" , "Puzzles and mysteries" , "Conundrums" , "Word games or sieves" , "Tricky questions" .)