How to make Steak and Mushroom Pie Mary Berry

Ingredients

• 500 g (1 lb 2 oz) puff pastry
• 5 tbsp sunflower oil
• 200 g (7 oz) smoked streaky bacon rashers, cut into 1 cm (0.5 inch) strips
• 2 medium onions, sliced
• 2 garlic cloves, finely chopped
• 850 g (1 lb 14 oz) well-marbled braising steak, trimmed of hard fat or gristle
• 500 ml (18 fl oz) bottle of local ale
• 500 ml (18 fl oz) good-quality beef stock
• 1 tbsp tomato purée
• 4 sprigs of thyme, leaves stripped from stalks
• 2 bay leaves
• 2 tbsp cornflour, blended with 2 tbsp cold water
• 250 g (9 oz) small chestnut mushrooms, wiped and halved or quartered if large
• Salt and freshly ground black pepper
• Beaten egg, to glaze