This term is not actually Spanish slang. It refers to a type of Italian dish which is a breaded steak with tomato sauce, ham, and cheese. It's widely known in Argentina due to the large Italian influence there.
Examples
- Spanish: Vamos a comer una deliciosa suprema napolitana en el restaurante italiano de la esquina.
- English: Let's eat a delicious 'suprema napolitana' at the Italian restaurant on the corner.