Swansea plant boxes American food (7)
I believe the answer is:
samosas
'swansea plant boxes' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'american food' is the wordplay.
I cannot really understand how this works, but
'american' could be 'am' (abbreviation in some contexts) and 'am' is found within the answer.
'food' could be 'a' (A is an example) and 'a' is present in the answer.
The remaining letters 'soss' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for samosas that I've seen before include "Triangular fried pastries" , "From parcels with spicy contents" , "snacks" , "lot of spicy food" .)