Cut the onion vertically into 4 sections, and then horizontally into 3 sections. Cut the kabocha into 3-cm cubes.
Add just enough water to a pot to cover the bottom. Add the onions and a pinch of salt. Clover with a lid and heat on medium heat. Once it comes to a boil, reduce to low heat and slowly simmer.
When the onions become half-translucent, add the kabocha, and place the miso on top of the onions in the center. Allow it to simmer without mixing.
When the water reduces and the miso starts to submerge into the water gently mix everything together. If there's still a lot of water left cook it off without covering with a lid.
When there's only a little water remaining, add the sesame seeds. Mix everything together and it's complete.
I used chickpea miso this time. It's a sweet and delicious miso. I checked with the Kushi Institute as to what miso they were using.