Heat half the oil in a large casserole pan. Cook the beef, in 2 batches, for 7 – 10mins until browned all over. Remove from the pan and set aside. Add the vegetables to the pan and cook for 5mins until soft.
Stir in the flour until well coated. Pour in the Guinness and stir around the pan, scraping up all the caramelised bits at the bottom of the pan.
Crumble in the stock cube, then return the beef to the pan with the thyme and top up with water if necessary. Cover and simmer for 1½hrs until the beef is really tender. Then leave to cool. Can be made up to 2 days in advance and stored in the fridge.
Preheat the oven to Gas mark 6/200°C/Fan 180°C. Spoon the beef and enough juice to cover it, into a large pie dish, removing the thyme sprig.
Place the pastry on top and cut away any excess with a sharp knife. Then use your fingers to crimp around the edge of the pie. Make a small slit in the centre of the pie for air to escape. Brush all over with the egg.
Cook for 30 – 40 minutes until golden and crisp. Heat any remaining beef liquid and serve alongside with some mash and greens.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.