1
general::
Phrase(s): upper crust
Fig. the higher levels of society; the upper class. (From the top, as opposed to the bottom, crust of a pie.) • Jane speaks like that because she pretends to be from the upper crust, but her father was a miner. • James is from the upper crust, but he is penniless.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
The highest social class, as in She wanted badly to be one of the upper crust but it wasn't going to happen. This term alludes to the choicest part of a pie or loaf of bread. [First half of 1800s]
American Heritage Idioms