The phrase is get yourjust deserts . . . not desserts. Although, I suppose you would get your just desserts if you were a good boy or girl and at all your meat andvegetables.
The word is deserts. Not desert (ˈdezərt) like a barren sandy waste land. Not desert (dəˈzərt) as is abandoning yourpost. But desert (diˈzərt) as in gettingwhat is coming to you.
My goodness, but the English language can be confusing.
Anyhoo, the problem with the word and why there is amisconception with which desert or dessert or whatever is used is because the desertthat is synonymous with deserves has fallen out of common usage and because itis pronounced like dessert.
So there you have it.