In a large stock pot add pork trotters and pork bones then fill it with water enough to cover everything. Bring it to a boil and continue to boil until the scum appears on top. Turn the heat off then drain.
Clean the pork bones and trotters in running water removing any scum that is stuck on it.
In clean stock pot add oil then sauté onion, garlic and ginger.
Add the pork trotters, bones, leeks, dried shiitake mushrooms and salt. Fill it again with water enough to cover everything (roughly 4 to 5 litres), cover with heavy lid then bring it to a boil.
Once boiling reduce to simmering heat and simmer for 4 hours, check water levels making sure it does not dry out, adding water if necessary.
After 4 hours, turn the heat off then strain the liquid using a fine sieve into a separate pot, reserve the bones.
At this point you need to have at least 3 litres of stock if not add water.
Place pot on stove top then bring it to a boil, once boiling lower to simmering heat.
Scrape off the very tender fat and skin from the trotter bones until you have around 1 1/2 cups of tender pork skin.
Place them in a bowl then using a hand blender puree them until smooth in consistency, pour this into the simmering soup.
Continue to simmer the broth for 2 more hours, season with salt then turn heat off.
Cook ramen noodles according to packet instructions.
Place ramen noodles in a bowl then pour the pork broth.
Top with thinly sliced Chashu pork, Boiled eggs, chopped spring onions, nori and menma.
