1. Dissolve yeast in warm water in a large mixing bowl. Let sit for 5 minutes.
2. Stir in sugar, melted butter, egg, and salt. Gradually add flour to form a soft dough.
3. Knead the dough on a floured surface until smooth and elastic, about 6-8 minutes. Place in a greased bowl, cover, and let rise until doubled, about 1 hour.
4. In a skillet, cook ground beef and onion over medium heat until meat is no longer pink. Add cabbage, salt, and pepper. Cook until cabbage is tender. Drain any excess fat.
5. Punch down dough and divide into 8 portions. Roll each portion into a 6-inch circle. Place about 1/2 cup of filling in the center of each circle. Fold dough over filling and pinch edges to seal.
6. Place bierocks on a greased baking sheet. Cover and let rise for 20 minutes. Preheat oven to 375°F (190°C).
7. Bake for 20-25 minutes or until golden brown. Serve warm.
Notes:
These bierocks can be frozen and reheated for a quick meal later.