Helen and Kate Mirren's Cabbage Pies

Ingredients

• 3 tbsp butter
• 1/2 cup water or chicken stock
• 1 medium white cabbage, thinly sliced
• 2 leeks, thinly sliced
• 1 medium onion, chopped
• 2 refrigerated pie crusts
• 3 hard-boiled eggs, chopped
• 3 tbsp chopped parsley
• milk, for brushing the crust