Powidl
Powidl (also porvidl, powidla, povidla, or powidel) is a fruit spread, prepared from the prune plum, that is popular in Central Europe. Unlike jam or marmalade, and unlike the German Pflaumenmus (plum puree), powidl is prepared without additional sweeteners or gelling agents. Powidl is cooked for several hours, in order to achieve the necessary sweetness and consistency. The plums used should be harvested as late as possible, ideally after the first frosts, in order to ensure they contain enough sugar. In Austria, Moravia and Bohemia, powidl is the basis for Buchteln, powidl cake and Germknödel, but it is also used as a sandwich spread. Powidl will keep for a long time, especially if kept in traditional crockery. Traditionally, large amounts of powidl to be used as a winter store and natural sweetener were prepared in late autumn during a communal event. Since constantly stirring the pot was exhausting work, people took turns, and did easier work in between turns. The Czech term povidla is plural only (the Polish word powidła as well). Traditionally the plums were "overcooked," (to promote evaporation) in a copper kettle, or sometimes vinegar preserved, or even steamed. One recipe for "dark red plum jam" (povidl) begins with placing the plums in a fermentation crock along with sugar and cider vinegar, and letting the mixture sit for a day before cooking. Another recipe for "traditional Austrian plum butter" recommends roasting the plums in an oven  and then transforming that compote-like dish into jam. Powidl is a key ingredient of the popular Austrian street food pofesen, which is a jam-filled form of French toast. See also 
Pączki
Lekvar
Apple butter
Varenye

References 

Translated from the corresponding article in the German Wikipedia, retrieved February 4, 2005. Austrian cuisine
Czech cuisine
Spreads (food)
Plum dishes
Polish cuisine