Braised Cabbage and beef buns (Piroshki)

Dough

• 2 cup Warm milk
• 1 tbsp Dried yeast
• ¹⁄₂ cup Sugar
• 6 cup Flour
• 3 Eggs
• 1 ¹⁄₂ tbsp Melted Butter
• 1 tsp Salt
• 1 Egg for wash

Filling

• 1 Cabbage
• 1 lb Beef mince
• 1 Onion
• 1 Carrot grated
• 1 cup Sauerkraut
• 1 tbsp Brown sugar
• 1 tsp Double cream
• ¹⁄₄ cup Water
• ¹⁄₂ tsp Salt
• ¹⁄₄ tsp Pepper
• 2 Bay leaves
• 3 tbsp Olive oil
• 4 tbsp Tomato puree