Slice the scallion into rounds and separate the white and green parts. the green parts will be reserved for garnishing the dish after cooking.
If you are hand-cutting your pork, it may be helpful to put the pork into the freezer for 15 or 20 minutes so that it firms up and becomes easier to cut.
Cut the pork into thin slices and shingle them on your cutting board.
Cut across the slices to yield thin strips of pork.
Turn the strips 90 degrees and slice them into a rough mince.
Place the thinly sliced shallot into a cold sautee pan with 2 tsp of neutral oil. Turn the heat to medium-high.
Cook the shallots over medium-high heat for about 5 minutes while constantly stirring.
When the shallots have started to get deep brown, add the chopped garlic and the scallion whites. Cook for 20 seconds.
Add the minced pork and break it up while cooking.
Continue to cook the pork while stirring until it has completely cooked through and any liquid released by the pork has evaporated.
Add 1 tbsp Shaoxing wine, 1 tbsp soy sauce, and 1/4 tsp dark soy sauce. Cook until the soy has absorbed into the pork, about 1 minute. Turn off the heat.
Place half of the pork mixture into the bowl in which you will be steaming the eggs and reserve the other half for garnishing the finished custard.