What is the traditional Dutch New Year's Eve doughnut called?

The traditional Dutch New Year's Eve doughnut is called an oliebol, plural oliebollen.

Oliebollen are deep-fried balls of yeasted dough, commonly made with currants or raisins and dusted with powdered sugar. They are sold by seasonal street stands and are strongly associated with the period around New Year's Eve and New Year's Day in the Netherlands and parts of Belgium.

The name literally means “oil ball,” referring to the frying method. Oliebollen are sometimes compared with doughnuts, but their shape, batter, and seasonal role are distinctive. Stories connecting them to older Germanic winter customs exist, although the exact historical development is more complicated than the simple claim that the recipe has one certain ancient origin.