Seafood and a US sausage (not Yankee) (7)
I believe the answer is:
abalone
'seafood' is the definition.
(type of sea snail)
'a us sausage not yankee' is the wordplay.
I cannot quite understand how this works, but
'a' could be 'one' and 'one' is present in the answer.
This explanation may well be incorrect...
'and' acts as a link.
Can you help me to learn more?
(Other definitions for abalone that I've seen before include "Edible shellfish, sea-ear" , "Seafood" , "Mollusc also called ormer" , "Ear-shaped shell" , "paua" .)