Friend entertains the Spanish with a dish of theirs (6)
I believe the answer is:
paella
'dish of theirs' is the definition.
I can't tell whether this defines the answer.
'friend entertains the spanish with a' is the wordplay.
'friend' becomes 'pal' (pal can mean a friend).
'entertains' means one lot of letters goes inside another.
'the spanish' becomes 'el' ('the' in Spanish).
'with' says to put letters next to each other.
'pal' placed around 'el' is 'paell'.
'paell'+'a'='PAELLA'
(Other definitions for paella that I've seen before include "Spanish dish of rice, shellfish, etc" , "Saffron-flavoured rice dish" , "Make stew" , "Spanish dish of rice, chicken, seafood etc cooked in a pan" , "Traditional Spanish dish" .)