Soup recipe secured by painter (6)
I believe the answer is:
borsch
'soup' is the definition.
(borsch is a kind of soup)
'recipe secured by painter' is the wordplay.
'recipe' becomes 'r' (abbreviation).
'secured by' means one lot of letters goes inside another (I've seen this in other clues).
'painter' becomes 'bosch' (I've seen this before).
'r' going within 'bosch' is 'BORSCH'.
(Other definitions for borsch that I've seen before include "Russian or Polish soup usually containing beet juice" , "Russian beetroot soup" , "Soup made with beetroot" .)