Start by preheating your oven to 200°C.

Separate the egg whites from the yolks.

In a separate bowl, combine butter and the first portion of sugar.

Add the cream cheese to the mixture and blend it well.

Gradually add the egg yolks, one at a time, ensuring each is well incorporated.

Pour in the milk, mixing until no clumps remain.

Sift in the flour and corn starch, mixing well to combine.

In another bowl, whisk the egg whites along with the cream of tartar. As you beat these, gradually add the remaining sugar until stiff peaks form. This should take roughly 5 minutes at high speed on a mixer.

Carefully fold the two mixtures together until they are well combined.

Prepare your pan by lining the bottom with baking paper and greasing the sides with butter.

Pour the batter into the prepared pan. (Avoid using a springform pan, but if it's necessary, wrap the bottom securely with aluminum to prevent water seepage.)

Arrange a water bath by filling a larger pan with hot water, about a third of the volume. Place the cheesecake pan inside this water bath and transfer both to the oven.

Bake the cheesecake for 15 minutes at 200°C. After this, reduce the oven temperature to 140°C and bake for a further 30 minutes. Finally, switch off the oven but leave the cheesecake inside with the oven door closed for another 30 minutes.