The Spanish-American sang backtrack coming out of Italian restaurant (8)

'the spanish-american sang backtrack coming out of italian restaurant' is the definition.
I can't tell whether this defines the answer.

'the spanish-american sang backtrack' is the wordplay.
'the spanish' becomes 'las' ('the' in Spanish).
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'backtrack' shows that the letters should be reversed in order (I've seen 'backtracking' mean this).
'sang' backwards is 'gnas'.
'las'+'a'+'gnas'='LASAGNAS'

Can you help me to learn more?