Heat up oil in a pressure cooker and fry the ginger, onions, and then brown the pork on the skin side.
Place all the liquid and bring to a boil.
Close the pressure cooker to cook for 30 minutes. If using a normal cooker, this can take 2-3 hours.
When done, take the pork out, cool and refrigerate. Place the peel boiled eggs into this liquid and cool together as well.
Remove the oil from the cooled cha su liquid, and strain.
Measure 4 cups of this liquid and mix with the dashi stock, bring to a boil and divide into 4 bowls. Season with salt (shio) or soya sauce (soyu).
Cook the ramen in hot salted water until al dente.
Add the ramen to the bowls of stock, and add the toppings.
This recipe yields 8 portions.