Prepare the Beef: Dice beef into 1-inch cubes. Coat with seasoned flour.
Cook the Filling: Sear the beef in olive oil until golden. Add tomato purée and stir for a minute. Pour in Guinness, then add shallots, thyme, bay leaves, and garlic. Simmer for 1 ½ hours, then discard bay leaves.
Assemble the Pie: Preheat oven to 200°C (390°F). Transfer beef mixture into an 8-inch pie dish. Cover with pastry, crimp the edges, and brush with egg wash.
Bake: Place on a baking tray and bake for 15-20 minutes until golden brown. Serve hot.