Take the dough out of the box and thaw it for at least 30 minutes at room temperature. You want the dough fully thawed, still cold, but not too soft and sticky. Chill one package in the fridge until ready to use.
In a large mixing bowl, add ground pork, onion, oyster sauce, fish sauce, sesame oil, salt and pepper. Combine well.
When the dough is thawed, preheat oven to 350 degrees fahrenheit.
Line your working station with parchment paper. Carefully unfold the dough and lightly roll it across the seams to make it even.
Cut the dough sheets into 9 even squares. You will see the two seams on the dough when you unfold and roll it out. Just cut along those two lines and then cut two more across. You’ll get 18 squares with one box of dough.
Scoop in about 2 tablespoons of the meat filling and place it in the center of one dough square.
Brush egg whites all four sides of the pastry square. Then place another square over. Use your fingers to press down on all sides to secure the filling in the middle and to seal the pastry.
Repeat with all the filling and dough.
Using the edge of a fork, press lightly to imprint lines on the edges and to further seal the sides.
Add water to the egg yolks and mix. Then brush the top of each pastry with the egg wash.
Place pastries on a baking pan lined with parchment paper about 1” apart and bake for 40 minutes at 350.
Transfer pastries to cooling rack until ready to serve.
Baking time is for two batches (40 minutes each) for 18 pastries. To store in the fridge, place the pâté chaud in an airtight container, it’ll keep for 3 days.To freeze, cool the pâté chaud and place in an airtight container and freeze. To reheat, bake at 350 degrees fahrenheit in a toaster oven for about 6-8 minutes.To reheat frozen pâté chaud, thaw them for at least 15 minutes at room temperature and bake at 350 degrees fahrenheit for 8-10 minutes.