I was trying to find the first reference to the El Diablo cocktail recently.
1 ounce tequila
1/2 crème de cassis
Squeeze lime juice into a 10-ounce glass; drop in spent shell. Add ice cubes, tequila, and crème de cassis. Fill glass with ginger ale.
Searching the web, the earliest reference I read to it was from Trader Vic's books of 1946 and 1947.
I asked tiki expert Martin Cate, who has these books, if he knew if the drink was a Trader Vic original. After his research it's still not entirely clear, but the research is interesting in itself.
If anyone finds an earlier reference to the El Diablo or Mexican El Diablo, please let me know.