Prepare the Filling:

1. Cut cabbage and onions fine. Heat 3 Tbsp Crisco in a large kettle or deep skillet.
2. Add cabbage, onion, salt, and pepper. Steam covered for about 30 minutes over medium heat. Stir occasionally.
3. In a separate skillet, brown the hamburger, breaking it apart as it cooks. Do not over-fry.
4. When the cabbage is nearly tender, mix the beef and cabbage together in the same pot. Cook another 20 minutes, adjusting seasoning to taste.
5. For moisture: cook and mash 1 potato. Use the mashed potato and its cooking water as part of the filling liquid (about 2 cups total). Stir into the beef-cabbage mixture.

Make the Dough:

1. In a bowl, scald the milk, then cool until just warm. Dissolve yeast in the warm water and add to milk.
2. Stir in sugar, shortening, egg, and salt. Mix well.
3. Add flour gradually until a soft dough forms (not too stiff). Knead until smooth.
4. Place in a greased bowl, cover, and let rise until doubled (about 1 ½ to 2 hours).
5. Punch down and let rest 10 minutes.

Assemble the Bierocks:

1. Roll dough out and cut into 3-inch squares.
2. Place 1 heaping Tbsp filling in the center of each square.
3. Pinch edges together to seal, forming a bun. Place seam side down on a greased baking sheet.
4. Bake at 375°F for 25 minutes, or until golden brown.