The information on this page is based on a recipe from the food blog Ice or Rice.

You can get all the ingredients in Chinatown. I usually get stewing chicken at Deluxe Food Market and the rest of the ingredients at Hong Kong Supermaerket.
Soak the dried shiitake mushrooms and a sheet of kombu in 12 cups of warm water for 20 minutes.
Meanwhile, heat a wok and add the ginger, garlic, onion, and leek. Stir occasionally until the vegetables are softened.
If you like a strong flavor, you can burn the vegetables a little bit.
In the Instant Pot, place shiitake mushrooms, chicken, bonito flakes, and the kombu-infused water (Step 1). Add the vegetables and cover with the lid.
Use the manual setting and set the timer for 60 minutes
When the cooking time is done, use the natural release, for at least 20 minutes.
Do not use the manual release since the liquid might spill.
Strain the broth using a colander. In a large saucepan, add the broth and bring it to a boil.
Mix miso paste with white miso, red miso, doubanjiang and sesame paste; mix well with the broth in the saucepan.
Cook noodles until barely tender. In a serving bowl, pour the broth over the noodles. Garnish with any toppings that you like.
One of the popular toppings, soft-boiled eggs, are also easy to make with the Instant Pot: place eggs with one cup of water, then set low pressure for five minutes. Then quickly release the pressure.