Mix together the lukewarm milk and oil in a large bowl. Add the eggs, yeast, sugar, salt and 5 cups of flour. Mix well and add remaining flour as necessary to to form a kneadable dough. Knead a few minutes. Cover bowl and let dough rise one hour in a warm place.
Meanwhile, brown beef in a large skillet. Do not drain. Add onion and cabbage and continue cooking until onion is soft. Add salt and pepper to taste. Let cool.
After dough has risen, roll out hunks of dough (about the size of a tennis ball) as thin as possible. Place 1/2 slice cheese on dough, top with some filling, then the other half slice of cheese. Fold over and seal like a turnover (moistening the edges with water may help seal them).
Place on a baking sheet, brush with egg wash and sprinkle with sesame seeds (optional) and bake at 350 degrees for about 30 minutes or until golden.
Serve immediately or cool and freeze. To reheat frozen, simply bake until hot.