Steam the kabocha squash, remove the skin, and mash it.
Soften cream cheese and mix with sugar.
Add eggs one at a time, mixing well after each addition.
Add the mashed kabocha squash and heavy cream, then mix to combine.
Sift in the flour and mix evenly.
Pour the batter into a pan lined with parchment paper.
Bake in a preheated oven at 200°C (392°F) for 35–40 minutes.
Let cool completely, then refrigerate for at least 4 hours.