What began as a pocketful of beef and cabbage eventually led to the Reuben we know and love today. Similar to the Cornish pasties popular in Michigan by way of Cornwall, the bierock is a sort of German calzone made from yeasty dough stuffed with beef, cabbage, and onions.
This portable sandwich precursor arrived in the Great Plains thanks to Germans who migrated from Russia to the Nebraska and Kansas farmland. Cabbage is a classic cold weather crop, and bierocks can warm you right up. The name bierock is probably related to the Russian pirozhki, another type of meat-stuffed dough dish. Perhaps not coincidentally, one of the several origin stories about the Reuben sandwich (more on that later) starts in Nebraska.
Baked in a half-moon or bun shape, bierocks are also called cabbage burgers, something my house boy remembers from growing up in Wyoming and is always threatening to make. Other fans refer to it as a runza, which inspired an entire chain of "ovenstuff'd sandwiches" in Nebraska. These oblong baked sammies look suspiciously similar to the cheesesteak pretzels that debuted last year.
Have you ever been to Runza or eaten a cabbage burger or bierock?
Source: Fork Fingers Chopsticks