Preheat your oven to 320°F. Prepare a 9-inch round cake pan by greasing it and lining the bottom with parchment paper.

In a large mixing bowl, beat the cream cheese with butter and milk until smooth and creamy. Add the egg yolks one at a time, mixing well after each addition.

Sift the all-purpose flour and cornstarch together. Gradually add to the cream cheese mixture, blending until well incorporated.

In a separate bowl, use an electric mixer to whip the egg whites until foamy. Gradually add the sugar, continuing to beat until stiff peaks form.

Gently fold the whipped egg whites into the cream cheese mixture. Be careful not to deflate the batter.

Pour the batter into the prepared cake pan. Tap the pan lightly on the counter to release any air bubbles.

Place the cake pan in a larger baking dish and fill the dish with hot water to create a water bath. Bake the cheesecake in the preheated oven for about 50 minutes.

Turn off the oven and let the cheesecake rest inside with the door slightly ajar for 10 minutes. Then remove it from the oven and water bath, and let it cool completely in the pan.

Once cooled, remove the cheesecake from the pan and transfer to a serving plate. Serve chilled, optionally dusted with powdered sugar or fresh berries.

Wrap any leftover cheesecake tightly in plastic wrap or store in an airtight container in the refrigerator for up to 5 days.