Tonight I finally had success with kabocha.
I adapted a recipe from Washoku, by Elizabeth Andoh. To me, reading this cookbook is like going to a spa. Everything about it is really beautiful. I would have been very surprised and disappointed if the recipe had failed.
The original recipe calls for ground chicken which is cooked after the kabocha, in the same broth. Instead I just stopped the recipe at kabocha and skipped the chicken altogether. As a result now I also have some very tasty soup broth that I can use to make something else.
The resulting kabocha has a subtle and smoky taste and a texture similar to that of roasted chestnuts. I will definitely make this again.