Kaiser roll also called a Vienna roll or a hard roll, is a typically crusty round bread roll, originally from Austria. It is made from white flour, yeast, malt, water and salt, with the top side usually divided in a symmetric pattern of five segments, separated by curved superficial cuts radiating from the centre outwards or folded in a series of overlapping lobes resembling a crown. The crisp Kaisersemmel is a traditional Austrian food officially approved by the Federal Ministry of Agriculture.
Semmel is the common name for any kind of roll in Austria and the German state of Bavaria, equivalent to Brötchen in Northern and Western Germany.
Kaiser rolls have existed in a recognizable form at least since prior to 1760. They are thought to have been named to honor Emperor Franz Joseph I of Austria. Indeed already in the 18th century, retail prices of Semmeln breadrolls were fixed by law in the Habsburg Monarchy. Allegedly the name Kaisersemmel came into general use, after the bakers' guild had sent a delegation in 1789 to Emperor Joseph II (1741–1790) and convinced him of decontrolling the selling price.
With its monarchal connotation, Kaiser rolls stood out against common rolls known as Mundsemmeln ("mouth rolls") or Schustersemmeln ("cobbler rolls"). They are traditionally found in Austria, but have also become popular in other countries of the former Austrian Habsburg Empire, such as Poland (known as kajzerka in Galicia), Slovenia (kajzerica), Croatia, Italy, Hungary (császárzsemle), as well as in Germany, the United States, and Canada. Italian bakers, during the Austrian domination in Lombardy, produced a hollow version known as michetta or rosetta.
A handmade Kaiser roll is known as a Wiener Kaisersemmel (Handsemmel) according to the Codex Alimentarius Austriacus standards collection.
There are multiple variants of the common roll, differing in size, type of flour used, and toppings. While traditionally plain, Kaiser style rolls are today found topped with poppy seeds, sesame seeds, pumpkin kernels, linseed or sunflower seeds. The Kaiser roll is a main part of a typical Austrian breakfast, usually served with butter and jam. It is often used as a bun for such popular sandwiches as hamburgers in America and with a slice of Leberkäse in Germany, though sliced Extrawurst and pickled gherkins (Wurstsemmel), or a type of Wiener Schnitzel (Schnitzelsemmel) are also used. A variation called a kummelweck (sometimes pronounced "kimmelweck" or "kümmelweck", from the Austrian Kümmelweckerl) is topped with kosher salt and caraway fruits, often served as part of a beef on weck sandwich.