Whisk the room temperature cream cheese until soft. Set it aside. Wrap the bottom of a 8-inch round cake pan by aluminium foil. Line the pan with baking paper.

Beat the egg yolk and add the condensed milk, shifted cake flour and cornstarch into it.(If you want the cake becomes more fluffy, you can add more cornstarch instead of cake flour). Mix well. Then mix it with the cream cheese.

Heat the milk and butter together until it is slight boil. Add 1/3 of milk into the step2 mixture. Stir it fast. Add the remaining milk and stir. Then put it into the fridge until need.

Preheat the oven to 150°C. Whisk the egg whites with sugar until soft peak is formed. Add the egg whites into the step3 mixture in several times. Use the hand mixer to mix it genteelly by hand. Pour the mixture into the cake pan in step1 and put it in the oven pan. Pour some water in the oven pan.