Married couple tucking into pastry dish in foil (6)
I believe the answer is:
thwart
'foil' is the definition.
(I know that foil can be written as thwart)
'married couple tucking into pastry dish' is the wordplay.
'married couple' becomes 'hw' (I can't justify this - if you can you should believe this answer much more).
'tucking into' indicates putting letters inside.
'pastry dish' becomes 'tart' (type of pastry product).
'hw' put inside 'tart' is 'THWART'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for thwart that I've seen before include "Snooker" , "Frustrate, prevent from doing" , "Hinder or prevent" , "Frustrate and obstruct" , "Frustrate or foil" .)