Æbleskiver are
a Danish pastry, roughly akin to doughnuts, or Sufganiot. Literally, æbleskiver (it's a plural) means apple slices (the singular form is æbleskive). They're usually described as spherical Danish pancakes; I would argue that they're lighter than pancakes. Traditionally they were made with small pieces of apple in the batter. They're cooked in a pan that's usually cast iron, though in the middle ages they were copper, with round indentations. You oil the pan, heat it, and pour the batter in the holes. The batter is made of eggs, milk (or cream or even buttermilk), a little salt, and a leavening agent (yeast or baking soda). As the batter cooks on the stove, you gently turn the browning æbleskiver, with a pair of knitting needles if you are a traditionalist, or a fork if you aren't. As it heats, the æbleskiver rise and become round and light. A perfect æbleskiver is round, and a uniform golden brown all over. The pan is quite hot, so you do need to pay attention and gently keep turning them so they cook evenly. In between batches, you can re-oil the pan with a brush or a paper towel.
Æbleskiver are served like a pastry or as a dessert while still warm, and dusted with powdered sugar. They're usually served after being dipped in jam, most often, raspberry jam, but they're lovely with other jams or with honey or even maple syrup (just don't tell any Danes). In Denmark, it's traditional to serve æbleskiver to guests in the weeks before Christmas, often accompanied with gløgg, the Scandinavian version of mulled wine. Æbleskiver freeze well, and you can often find a commercial mix at stores or even online, where you can also find a proper æbleskiver pan (you can make your own batter, but the pan is crucial). It's also important to separate the eggs, and beat the egg whites; they help make æbleskiver light and puffy.
Even when it's not Christmas, you can often find local Danish or Scandinavian festivals serving freshly made æbleskiver. In the late summer or early fall, Solvang, California celebrates its Danish heritage with Danish Days, and the Solvang restaurant makes thousands of æbleskiver to serve visitors. This year the three-day festival starts on Friday, September 17 and runs through Sunday. On both Saturday and Sunday, from 8:00am to 12:30pm, there's an Aebleskiver Breakfast on Copenhagen Drive & First Street in Solvang.
Lan Palmer from The Solvang Restaurant shows you how to make æbleskiver.

