Defrost the puff pastry. Take the puff pastry out of the freeze for 2 hours before you plan to assemble and bake the pate chaud. Leave it out to defrost on the counter. Alternatively, you can take the puff pastry out of the freezer the night before and defrost it in the refrigerator overnight.
Mix the meat filling. Combine the ground pork, onion, shallot, wood ear mushroom, oyster, sauce, sesame oil, salt, black pepper, sugar and fish sauce. Mix well. Refrigerate if you are waiting for the puff pastry to defrost.
Prepare the puff pastry. When the puff ready is ready to be used. Take them out of the box and remove the plastic wrap. Depending on the brand it will either be rolled up with parchment paper or folded without parchment paper. Take a rolling pin and roll the sheets flat. Only handle the sheets you are using first. Take a pizza cutter or pasta cutter and cut and cut the sheets into roughly 3-inch X 3-inch squares.
Assemble. Spoon approximately 1 ½ -2 tablespoons of the meat filling onto the centre of each square of puff pastry. Use the egg whites and paint the sides and place another square of puff pastry on top. Using your fingers gently press down all four sides. Take a fork and press down on all four sides to give it a nice edge.
Repeat. Once you are don’t with the first box of puff pastry repeat step 3-5 with the remainder of the pork filling.
Preheat your oven. Preheat the oven to 375°F.
Egg wash and bake. Coat the puff pastry with the egg wash using a silicone brush. Bake the puff pastry on the middle rack for 30 mins or until it is puffed up and golden brown on the top. Take out and let it rest for 5 minutes and transfer to cooling rack. Add some black sesame seeds on top to give it a bit of color (Optional).