Pour rice brain oil into a stock pot and cook of onions, white part of the scallions, garlic and ginger for 5-7 minutes on medium-heat or until caramelized.
Stir in the chili paste and cook until aromatic, before adding the mushrooms and stirring for a further 5 minutes or until mushrooms get a slight brown edge.
In a small bowl whisk the miso paste and 1 cup of stock before adding to the pot of mushrooms, then add in the rest of the stock and the soy sauce to the pot.
Bring to a boil turn heat to low and cover with a lid, allowing to simmer for 1-3 hours.
In the time the broth is simmering cook the pork belly. Preheat oven to 310 degrees F.
Rub pork belly all over with salt and pepper then place on a rack above a baking sheet into the oven to cook for 90 minutes to 2 hours or until pork belly is cooked through. Turn oven to hottest temperature and blast belly to get crispy skin for 10-20 minutes. Remove and set aside.
Bring a small pot of water to a boil, using a spoon, carefully place the eggs in, set a timer for 5 minutes 45 seconds. Once alarm goes off shock eggs in a bowl of ice water and peel.
Using same pot of water, bring it back to a boil and add the noodles for 1-2 minutes or until it reaches desired consistency.
To serve add noodles to a bowl, poor over miso broth and top with 3 slices of pork belly. Sprinkle over green scallions and serve with black sesame seeds.