For the burger filling: Brown the ground chuck in a large skillet over medium heat, crumbling the meat pretty finely as it browns. Add the chopped onions and 1 teaspoon of the pepper. Cook the onion down a little, 3 to 5 minutes. Add the chopped cabbage, sauerkraut, remaining 1 teaspoon pepper and 1 teaspoon salt. Let the mixture cook, 10 to 15 minutes, depending on how done you like the cabbage. Strain and let cool.
For the dough: Put the yeast and sugar in a 4-cup measuring cup and add warm water to the 1-cup mark. Stir together and let sit until the yeast rises to twice its original size. Put the powdered milk in another 4-cup measuring cup and add water to the 2-cup mark. Stir together. In a large mixing bowl, add the flour, salt and shortening. Cut the shortening into the flour by hand. Next, make a well in the flour and add the eggs, yeast mixture and the powdered milk mixture to the flour. Work it all together until the dough comes away from the bowl (you may need a touch more flour or water). Oil the dough slightly on each side, cover and let rise, for 10 minutes. Pinch and let rise another 15 minutes.
To assemble the Lauer-Kraut burgers: Preheat the oven to 350 degrees F. Line a baking sheet with parchment paper.
Lightly flour a work surface and put the dough on the flour. Begin to roll the dough as close to a rectangle as you can, roughly 24-by-30 inches. Once the dough is rolled out, cut the dough into squares, roughly 6-by-6 inches. Take a square of dough and roll it out a little bigger, roughly 8-by-8 inches. Turn the re-rolled square over and add a full cup of filling mixture into the middle of the dough. Bring the opposite corners of the square together, and then bring the other 2 opposite corners together. You should have all 4 corners drawn together. Pinch down the 4 seams of the dough. Once you pinch all the seams, push down slightly on the kraut burger. This will release extra air and help you find any place you missed sealing the kraut burger. Turn the sealed pocket over and place it on the prepared baking sheet. Repeat with the remaining ingredients. Bake for 15 to 20 minutes.
Recipe courtesy of Mama Lori Lauer "The Boss," Lauer-Krauts, Brighton, CO