revenge is a dish best served cold

Earliest known metaphorical reference to revenge as food in English is “And then revenge is very good eaten cold, as the vulgar say”, from an 1846 translation of Eugène Sue's Mathilde: Mémoires d'une Jeune Femme. The passage suggests that it was an existing expression. Similar proverbs are known as early as the 17th century with “Reuenge is not good in cold bloud” in a translation of Don Quixote. The phrase exists in various Romance languages: Italian la vendetta è un piatto che va servito freddo, Spanish la venganza es un plato que se sirve frío, French la vengeance est un plat qui se mange froid. In French, it's commonly used since at least the 19th century. In English, many variations are attested but the exact phrase revenge is a dish best served cold may originate from the 1982 film Star Trek II: The Wrath of Khan.

来源：wiktionary