GTK+ what is a popover?

[Fòram na Gàidhlig <fios foramnagaidhlig net>]

Hi all,

I am stuck trying to translate the word popover, because I have no idea 
what it means. I'm leaving it in English for now.

Web search only gives me definitions à la "light, hollow roll made from 
an egg batter similar to that of Yorkshire pudding, typically baked in 
muffin tins or dedicated popover pans, which have straight-walled sides 
rather than angled." *lol*

Has anybody had any inspiration for this so far, and what do the things 
look like?