01 - Preheat the oven to 400°F (200°C conventional / 350°F fan). Line a baking tray with parchment paper and set aside.
02 - Heat olive oil in a frying pan over medium-high heat. Add the finely chopped onion and cook for 2 minutes until softened. Add minced garlic and stir for 30 seconds until fragrant.
03 - Add the diced steak to the pan and sear until browned on all sides, approximately 3 minutes. Season with Worcestershire sauce, salt, and black pepper, stirring to coat evenly.
04 - Sprinkle all-purpose flour over the steak mixture and stir thoroughly to combine. Pour in the beef stock and continue cooking for 2 to 3 minutes until the liquid thickens into a glossy sauce. Remove from heat and allow to cool slightly, then fold in the grated cheddar until melted and evenly distributed.
05 - Unroll the puff pastry onto a lightly floured work surface. Using a sharp knife, cut the sheet into four equal rectangles.
06 - Spoon equal portions of the steak and cheese filling along one long edge of each pastry rectangle.
07 - Brush the pastry edges with beaten egg. Fold the pastry over the filling and press firmly to seal. Place each roll seam-side down on the prepared baking tray. Crimp the edges with a fork to ensure a tight seal.
08 - Cut a few small slits in the top of each roll to allow steam to escape during baking. Brush the tops generously with remaining beaten egg for a golden finish.
09 - Bake in the preheated oven for 20 to 25 minutes until the pastry is puffed, golden brown, and crisp to the touch.
10 - Remove from the oven and allow the rolls to cool slightly on the tray for 5 minutes before serving.