Cocktail + dash lemon juice served up in a sugar rimmed glass and garnished with a long lemon peel.
For the most part a Crusta is a gussied-up cocktail. Jerry Thomas’ recipe simply took a fancy cocktail and added a dash of lemon juice to it, then served it in a sugar rimmed glass (hence the name Crusta), and garnished it with a wide spiral slice of lemon peel. Apparently first invented around 1850 in New Orleans, this drink never quite made it to the big time like the cocktail did. For an example, see: