Russian Kulebyaka (Stuffed Pie)

Ingredients

• 300 g plain flour
• 7 g dried yeast
• 1 tsp sugar
• ½ tsp salt
• 150 ml warm milk
• 1 egg
• 50 g unsalted butter (melted)
• 300 g salmon fillet (skinless and boneless)
• 100 g cooked rice
• 3 hard-boiled eggs (chopped)
• 100 g white cabbage (finely shredded)
• 1 small onion (finely chopped)
• 2 tbsp fresh dill (chopped)
• Salt and black pepper to taste
• 1 tbsp butter (for cabbage)
• 1 tbsp oil (for onions)
• 1 egg yolk mixed with 1 tbsp milk