Peel the kabocha squash, remove the seeds, and cut into small pieces.
Drain the tofu and dice it into cubes.
Finely chop the onion.
Heat olive oil in a pot and sauté the onion.
Add the kabocha squash and stir-fry together.
Pour in water or vegetable broth and boil until the kabocha squash is cooked through.
Add the tofu and simmer once more.
Blend until smooth with a blender.
Season with salt and pepper.