- Soak kombu in the water for 30 mins in a pot and turn on the heat to medium. Remove from heat when water begins to boil.
- Add bonito flakes then return to heat. Allow the water to simmer for another 1 min.
- Strain the stock into a clean bowl.
- Boil the spinach in the water and drain when done. Divide into 4 portions and set aside.
- Add the mirin, soy sauce, and salt to the dashi stock. Portion a quarter of the dashi stock into 4 individual sized clay pots.
- Add the chicken to the soup and simmer until it has cooked through.
- Add in the udon noodles, and let it cook for a few mins as per packet instructions.
- Place the kamaboko and a portion of boiled spinach on top and simmer in the soup for a few mins.
- Drop in an egg into the broth. Then add a few slices of leek on top.
- Remove the clay pot from the heat and serve hot.