Wash thoroughly the Kombu and add to a big pot along with the water. Bring to a boil on high heat and let simmer for 10’. Remove the kombu from the pot and discard.
Increase the heat and add to the pot the mushrooms, bring to a boil and let simmer for 40’. Remove the mushrooms from the pot and keep aside to be used in the building of the dish.
Once again turn up the heat and put the chicken in the pot. Once it boils allow to simmer for about an hour and until the meat is almost falling apart. In-between, use a slotted spoon to remove any foam or scum created on the surface. Replenish the water as part of it may evaporate during the cooking process. Remove the chicken from the pot and keep aside to be used in the building of the dish.
As the water simmers add the bonito flakes to the pot and allow to flavour the broth for 20’. With a slotted spoon remove as much as possible of the bonito flakes and discard.
Add to the pot the onions, scallions and carrots along with the sugar and the soybean paste, mix well for the paste to be diluted and simmer for 60’. At the last 5’ pour the sake to the pot. Taste the broth and adjust with a bit of soy sauce or sugar if needed.
Run the broth through a cheese cloth and discard the veggies and any solids that were in the broth. Keep the broth warm to be used in the noodles.
To cook the noodles, place a large pot filled with salted water on high fire and once it boils add the noodles and cook according to package instructions. Remove from the heat, drain and keep aside.
In the meantime, turn the oven on with the broiler/griller chosen and rack placed on the top position. Take the chicken fillets off the body of the chicken, glaze with some Miso Sauce and place in a cooking tray. Place the tray in oven and cook near the griller for 4-5’ for the miso sauce to char a bit. Remove from the oven and slice into 1cm thickness slices.
To put everything together take a deep bowl and add some noodles. Then pour all-over couple ladles of broth, add 4-5 slices of chicken on the side of the bowl and add next and around to them the bean sprouts, soybeans, couple of bok choy leaves, bamboo shoots, shitake mushrooms, enoki mushrooms, sliced scallions as well as a halved egg right in the middle. Pour a tbsp or two of Mirin, at your choice add some sriracha sauce and garnish with red chilli pepper threads and sesame seeds. Finally, deep halfway in and on the side of the bowl a nori sheet and enjoy.