The story
Pseudo-Gallicism (formed within English), from café (“coffee”), with postpositive (as usual in French) royale f, royal m (“royal”). Although café is masculine, the feminine form royale is used.
First known use, by meaning
- from 1890 Coffee with brandy, sometimes served with spices, cream, etc.; (countable) a serving of this beverage.
Etymology from Wiktionary, CC BY-SA 4.0.