A popover is like Yorkshire pudding. The batter is very similar. Sometimes in fact the line between a popover and a Yorkshire pudding gets blurred.
In general, popovers are made without the beef dripping, so they are somewhat drier. Some think that Popovers cry out to be torn in half and smeared with butter.
In Yorkshire pudding, the fat is part of the flavour. In popovers, the fat is mostly to make sure they come out of their tins more easily.
A popover doesn’t have the soft, less-risen part in the middle that Yorkshire pudding does because it rises more, and comes out taller and puffier.
To make popovers, muffin tins are heated, then brushed with butter or shortening (in Yorkshire pudding, the fat is put in the tins first, then superheated with the pans.) The batter is poured in, and baked.
Literature & Lore
“That ethereal puff, the popover, has been ready-mix mastered, the handiwork of a man. New cooks need no longer shy away from those tall hot breads ‘all air in the middle.’ The new ready-mix, ‘Puff-Over’ by name, gives a pop-over that pops up and stays up every time. Truth is, popovers take no extraordinary sort of skill despite their spectacular appearance, but women think they do. They’re an easy luxury composed of nothing but expanding steam and the stretching qualities of gluten and egg and the ability of heat to set the bubble into a great golden puff.” — Paddleford, Clementine (1898 – 1967). Food Flashes Column. Gourmet Magazine. October 1944.