Mix well beef, panko bread crumbs, garlic powder, salt, and black pepper in a bowl.
Beat an egg and a pinch of salt in a small bowl.
Onto the floured surface, roll out puff pastry then slice it into two parts, length-wise.
Divide the meat mixture in two and form a roll, the same length as the puff pastry. Place on top of the puff pastry.
Then roll the puff pastry until it covers up the meat mixture.
Cut the roll into 8 equal parts each long beef roll.
Place the beef sausage rolls on a baking sheet that is covered with parchment paper then brush them with egg.
Bake at 350° F for 25-30 minutes.
When done baking, serve it.