Grease and line the bottom and sides of a 20-cm springform cake pan. Wrap the outside of the pan with foil. Make sure the foil comes up all around the sides to about half the height of the pan. Pre-heat oven to 160 deg C. Prepare a water bath by filling a baking tray large enough to hold the cake pan, with water. Fill the pan up to a height between 2 to 2.5 cm, with water.

Place A in a mixing bowl and stir over double boiler (read notes below) until mixture becomes thickened, almost like custard. Remove from double boiler.

Add B and mix until well combined. Add C, one yolk at a time, mix until well blended.

In a dry mixer bowl, whip egg whites in D until foamy. Then add the cream of tartar. Then add sugar in a slow, continuous stream, and lastly, salt. Continue whipping until soft peaks.

Fold the egg white mixture from (4) into the cheese mixture from (3) above, until well incorporated.

Pour the cheese filling into the prepared cake pan. Bake in water bath at 160 deg C for 45 to 60 mins. The cake is done when firm and golden brown. Test if cake has completely baked through by inserting a bamboo skewer in the centre of the cake. It should come out clean.

Remove cake from the oven. Remove the cake from the mould immediately. Set aside to cool.