Soften the kabocha squash in a microwave and mash it while it is still hot.
Mix in all of the sugar and the milk a little at a time.
Add the well beaten egg and mix again.
Strain through a sieve. Strain through any kabocha squash that remains in the sieve.
Pour the mixture into the jars or containers you will use and loosely wrap with cling film.
Line an earthenware pot that contains 2 cups of boiling water with aluminium foil and let the jars stand inside. Put a lid of the pot and heat for 2 minutes on a medium heat. Once heated, turn off the heat and leave for a further 15 minutes.
After 15 minutes, remove the jars from the earthenware pot and leave them to cool in the refrigerator to finish.
Here's the finished pudding.
Story Behind this Recipe
This is the kabocha squash version of the earlier Earthenware Pot Custard Pudding recipe (Recipe ID: 878739).
If you increase the number of times you strain the mixture it will become even smoother.