Steam pushes the batter up and over the top of the pan to form the crusty, craggy crown of a popover.
Beat the batter just until smooth; overbeating it can break up the structure.
Pour batter into every other cup if your muffin tins have less than 1 inch between cups; popovers need room for their tops to expand.
Fill cups 3/4 to almost full, so batter can pop up over the edges.
Puncture popovers once they have puffed and the shell has set (to release the steam); return them to oven to firm up.
Popovers are perfect vehicles for both savory and sweet fillings: Split large ones open and spoon in softly scrambled eggs; top with cheese and salsa or diced tomatoes. Or for dessert, slit popover tops open and fill with a scoop of vanilla or chocolate ice cream; top with peeled orange segments and caramel sauce.