01 - Combine ground pork, onion, garlic, soy sauce, oyster sauce, sugar, black pepper, salt, cornstarch, and sesame oil in a mixing bowl. Mix thoroughly until well incorporated and smooth.
02 - Preheat oven to 400°F. Line a baking tray with parchment paper.
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 or pastry cutter.
04 - Place 2 tablespoons of meat filling in the center of 5 pastry circles. Leave a small border around the edges.
05 - Brush the edge of each filled circle with beaten egg. Cover with a second pastry circle, pressing firmly to seal. Crimp edges with a fork for a secure seal and decorative finish.
06 - Brush tops of sealed pastries with remaining beaten egg for a golden, glossy finish.
07 - Transfer pastries to the prepared baking tray, spacing them 2 inches apart to allow for expansion during baking.
08 - Bake for 20 to 25 minutes, or until pastries are puffed and deeply golden brown. Rotate tray halfway through for even browning.
09 - Let cool on the baking tray for 5 minutes before serving warm.