Preheat your oven to 320 degrees Fahrenheit (160 degrees Celsius).
Using parchment paper, line the bottom of a round cake pan that is 8 inches in diameter. Butter should be used to gently grease the sides.
To make the cream cheese mixture, combine the cream cheese, butter, and milk in a dish that can withstand high temperatures.
The bowl should be placed over a pot of water that is simmering (a double boiler), and the mixture should be heated while being stirred regularly until it is completely smooth and fully mixed. Take it off the heat and let it to cool down a little bit.
For the dry ingredients, combine the cornflour and cake flour and sift them together. Put away for later.
To prepare the egg yolks, place them in a large mixing basin and whisk them until they become light and pale.
After allowing the cream cheese mixture to somewhat cool, add it to the egg yolks and whisk it until it is completely incorporated.
Until the mixture is completely smooth and free of lumps, gradually include the flours that have been sifted.
The egg whites should be beaten in a separate, clean mixing dish until they turn into a frothy consistency. After adding the cream of tartar (if you are using it), continue beating the mixture until soft peaks emerge.
While continuing to beat the egg whites until stiff peaks form, gradually add the sugar to the egg whites, a little at a time.
In order to combine the ingredients, carefully incorporate the egg white mixture into the cream cheese batter in three separate additions, taking care not to deflate the batter completely.
Pour the batter into the cake pan that has been prepped for baking.
Remove any air bubbles that may be present by softly tapping the pan on the counter.
It is necessary to make a water bath by placing the cake pan inside of a bigger baking pan and then filling the larger pan with boiling water.
Bake for about sixty to seventy minutes in an oven that has been preheated, or until the bottom is golden brown and a skewer that has been pushed into the middle comes out clean.
When it comes to cooling, be sure to turn off the oven and keep the cake inside with the door slightly ajar for around fifteen minutes. This will avoid any rapid swings in temperature.
After taking the cake out of the oven from the water bath, place it on a wire rack and allow it to cool fully in the pan by itself.
The cake should be removed from the pan with caution after it has cooled.
Before serving, sprinkle powdered sugar over the top of the cheesecake to provide a finishing touch.
Enjoy your fluffy Japanese cotton cheesecake by slicing it and eating it!
