Cut a strip of parchment that is 3 cm higher than the height of the cake pan. Fold 1.5 cm along the long edge and cut a notch to the fold line every 2 cm to allow the strip to line the side of the cake pan. Slits should point into the center of the cake pan. You want the strip to be at least 1 cm taller than the cake pan. (Basically, the notches are just so you can build a perfectly round collar around the base of the pan.) Cut a parchment paper round to line the bottom of the cake pan.
Preheat the oven to 355°F. Put the egg whites into the freezer so it just begins to freeze around the edges. Sift the cornstarch.
Wrap the cream cheese in clear wrap and microwave until it becomes soft to the touch. You do not want to heat it up. (I did this in about 15 second intervals.)
In a large bowl, melt the butter over a double boiler. Add the cream cheese and whisk well to combine.
In another bowl, combine the egg yolks and 20g of sugar. Mix in the cornstarch.
Heat the milk so it comes to a boil. Add it to the egg yolks and whisk until it thickens in a double boiler over boiling water. Add this mixture to the cream cheese and combine well.
Add a small amount of the 55g of sugar to the egg whites and mix on medium low speed for about 2 minutes. Gradually add the remaining sugar to the egg whites and beat on medium until a soft meringue forms.
Add ¼ of the meringue to the cream cheese mixture and combine. Add the remaining meringue to the cream cheese mixture and fold to combine. Fill the cake pan and smooth the top.
Put the cake pan in a roasting pan and add boiling water so it comes up 1-1.5 cm up the cake pan. Bake for 15 minutes and then lower the temperature to 160°C and continue to bake for 25 minutes until the top turns slightly golden. Turn off the oven and leave the cake pan for another 40 minutes to an hour.
Note: The cake will continue to bake with the heat off so do not over bake. Depending on the oven, the cake may not turn golden but should avoid cooking much longer than the suggested time.
Take the cake out of the roasting dish and place on a wire rack to cool completely. Refrigerate and chill completely before taking it out of the pan. It is best served the second day