Russian Mennonite zwieback is a yeast bread roll

Bread roll

A bread roll is a piece of bread, usually small and round and is commonly considered a side dish. Bread rolls are often used in the same way as sandwiches are—cut transversely, with fillings placed between the two halves.-Various forms:...

 formed from two pieces of dough that are pulled apart when eaten. Placing the two balls of dough one on top of the other so that the top one does not fall off during the baking process is part of the art and challenge that must be mastered by the baker. Traditionally, this type of zwieback is baked Saturday and eaten Sunday morning and for afternoon Faspa.

Russian Mennonite zwieback originated in the port cities of the Netherlands

Netherlands

The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

 or Danzig, where toasted, dried buns were used to provision ships. Mennonite

Mennonite

The Mennonites are a group of Christian Anabaptist denominations named after the Frisian Menno Simons , who, through his writings, articulated and thereby formalized the teachings of earlier Swiss founders...

immigrants continued this practice centuries later.