Galbi Steak Pie

Ingredients

• 700g (1lb 9oz) short ribs of beef, cut into 2.5cm (1 in) cubes
• 50g (2oz) plain flour, plus extra for dusting
• 25g (1oz) butter
• vegetable oil
• 2 medium onions, cut into 3cm (1 ¼ in) dice
• 1 tsp ginger, grated
• 1 tsp garlic, grated
• 150ml (5fl oz) Guinness beer
• 120ml (4fl oz) soy sauce
• 3 Tbsp mirin
• 1 Tbsp roasted sesame oil
• 2 Tbsp brown sugar
• 300ml (10fl oz) beef stock
• 185g (6 ½ oz) baby potatoes
• 2 large carrots, peeled, halved lengthways and cut into half moons
• 175g (6oz) mixed mushrooms, trimmed and halved if large
• 1 tsp freshly ground black pepper
• 1 egg
• 275g (10oz) puff pastry
• sea salt