01 - In a mixing bowl, combine ground pork, onion, garlic, soy sauce, oyster sauce, sugar, black pepper, salt, cornstarch, and sesame oil. Mix thoroughly until well incorporated and seasonings are evenly distributed throughout the meat.
02 - Preheat oven to 400°F. Line a baking tray with parchment paper and set aside.
03 - On a lightly floured surface, roll out puff pastry sheets to about 1/8 inch thickness. Cut into 10 circles using a 3.5-inch round cutter.
04 - Place 2 tablespoons of meat filling in the center of 5 pastry circles. Brush the edges with beaten egg. Cover with remaining pastry circles, pressing firmly to seal. Crimp edges with a fork for decorative finish.
05 - Brush tops of assembled pastries with remaining beaten egg to achieve golden-brown finish.
06 - Arrange pastries on prepared baking tray, leaving space between each for expansion. Bake for 20-25 minutes until puffed and golden brown.
07 - Let cool slightly for 5 minutes before serving warm.