The misspelt phrase just desserts appeared in a recent Businessweek article. (It’s now fixed, so here’s a screenshot; I’m sure I wasn’t the only one to alert them.) This is a common error even in careful writing, and it’s an understandable one. The correct spelling is just deserts. It means “what one deserves or merits” – usually punishment.
Because it’s spoken with stress on the second syllable – just deserts – many writers infer the spelling desserts, a familiar word pronounced the same way. Dessert comes from French dessert, from Latin desservir “clear the table”, literally “un-serve” or “de-serve”.
The similar Latin word deservire “serve well” or “merit by service” led to Old French deservir “deserve”, the feminine past participle of which is deserte. This entered Middle English as desert: “what is deserved”. It’s an altogether different noun (with different origin) from the Sahara or Antarctic type of desert, an arid place with little or no vegetation.
Shakespeare used desert this way. From Sonnet no. 72:
Unless you would devise some virtuous lie,
To do more for me than mine own desert,
And hang more praise upon deceased I
Than niggard truth would willingly impart
Nowadays, desert (n.) is seldom used in contexts other than just deserts, so it’s no surprise people don’t know it. Maybe they see *just desserts as a food-inspired metaphor: a fitting outcome after an event, like a tart that can be sweet or rotten depending on what poetic justice ordains. It’s a coherent but misleading folk etymology.
To bring the correct spelling more readily to mind, decline dessert. Remember the little-known noun desert and its connection to one-s deserve: just deserts are what one justly deserves.