For the marinade: Mix the chicken base, soy sauce, sugar, food coloring, salt and pepper in a bowl. Cut pork in half horizontally to make two long, flat thin pieces (for better flavor penetration). Put the pork in a stainproof container or resealable plastic bag and pour in the marinade. Marinate 20 minutes in the fridge.
Preheat oven to 425 degrees F. Line a baking sheet with foil and place a rack on top. Remove pork from the marinade and place on rack. Roast, about 45 minutes. Let pork rest for 10 minutes, then dice.
For the dough: Meanwhile, combine the flour, sugar, butter, yeast, egg and 1/2 cup warm water in a mixing bowl and blend for 10 minutes. Let sit for 3 hours.
Preheat the oven to 425 degrees F. Cut twelve 3-inch pieces of wax paper and set aside.
Roll dough by hand into a cylinder with a 1 1/4-inch diameter. Cut into 12 equal pieces. Roll each piece into a ball and flatten into a 3-inch pancake.
Add some pork to the center of a pancake, then fold the edges of the dough over the pork and bring together. Repeat with remaining pancakes and pork, placing completed buns on squares of wax paper.
Place completed filled buns on waxed paper and brush tops with mayonnaise and condensed milk. Bake, about 15 minutes.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Grand Harbor, San Francisco, CA