Step 1: Prepare Your Equipment

1. Preheat your oven to 320°F (160°C). Grease a 7-inch (18cm) round springform pan or cake pan and line the bottom with parchment paper. Wrap the outside of the pan in two layers of aluminum foil to prevent water from seeping in during the water bath.
2. Place the prepared pan inside a larger baking dish to set up for the water bath later.

Step 2: Make the Cream Cheese Mixture

3. In a heatproof bowl, combine the cream cheese, butter, and milk. Place the bowl over a pot of simmering water (double boiler setup) and whisk until the mixture is smooth and fully combined. Remove from heat and let it cool slightly.
4. Once cooled, whisk in the egg yolks, vanilla extract, and lemon juice (if using) until smooth.

Step 3: Add Dry Ingredients

5. Sift the cake flour, cornstarch, and salt into the cream cheese mixture. Gently whisk until the batter is smooth and lump-free. Avoid overmixing to maintain a light texture.

Step 4: Whip the Egg Whites

6. In a clean, dry mixing bowl, use an electric mixer to beat the egg whites on medium speed until foamy. Gradually add the granulated sugar (a little at a time) while continuing to beat. Increase the speed to high and whip until the egg whites form stiff, glossy peaks.

Step 5: Fold the Batter

7. Gently fold one-third of the whipped egg whites into the cream cheese mixture to lighten it. Use a spatula and a gentle folding motion to avoid deflating the batter.
8. Add the remaining egg whites in two additions, folding carefully until just combined. Ensure there are no visible streaks of egg whites.

Step 6: Pour and Prepare the Water Bath

9. Pour the batter into the prepared pan and tap it lightly on the counter to remove any air bubbles. Place the pan inside the larger baking dish, and pour hot water into the baking dish until it reaches halfway up the sides of the cake pan.

Step 7: Bake the Cheesecake

10. Bake in the preheated oven for 60–70 minutes, or until the cake is golden on top and set in the center. The top should spring back lightly when touched.
11. Turn off the oven and leave the cheesecake inside with the door slightly ajar for 15 minutes. This prevents sudden temperature changes that could cause the cake to collapse.

Step 8: Cool and Serve

12. Remove the cake from the oven and water bath. Let it cool to room temperature in the pan, then refrigerate for at least 2 hours (preferably overnight) for the best texture.
13. Remove the cake from the pan, dust with powdered sugar if desired, and slice. Serve with whipped cream, fresh fruit, or a drizzle of compote.