птичье молоко

птичье молоко (literally: "bird's milk")

Example: The best pastry I had in Russia is called "Bird's Milk Cake". The name comes from an old Russian saying "you have everything but bird's milk". I first had it at Vladimir's house, and again in St. Petersburg and it's very good. (Wade's Vision Quest Journal, Russian Food)

In Russian fairy tales, "bird's milk" is a luxury so fantastic it doesn't even exist.

Тебе что, птичьего молока надо? Птичьего молока не хватает?
An egg in your beer?

Example 1: "You've got a good job, and a nice house! What else? An egg in your beer?" - "У тебя и так есть хорошая работа и прекрасный дом. Чего тебе еще не хватает? Птичьего молока?"

Example 2: When I was quite young, my Mom's expression was "Whadaya want; an egg in your beer?" when I'd been given something, but was whining for something else to go with it (SF)

This dates back as far as the WWII when both food items were scarce and having either was considered extremely lucky. 'Egg in your beer' is normally used to stop somebody complaining about a situation you think to be favourable.

Pelated vocabulary: