Start by preheating your oven to 320°F (160°C). Line your 12-cup muffin tin with cupcake liners. Separate your eggs into yolks and whites. It's crucial to keep the mixing bowls clean and grease-free when whipping the egg whites to ensure they reach stiff peaks.

In a medium saucepan over low heat, combine the cream cheese, butter, and milk. Stir continuously until smooth and fully melted. Be careful not to overheat; the mixture should be warm, not boiling. Remove from heat and let it cool slightly.

Once cooled, whisk in the egg yolks, vanilla extract, and lemon juice until fully combined. Gradually fold in the sifted flour and cornstarch, making sure there are no lumps.

In a clean, dry bowl, beat the egg whites with a pinch of salt until foamy. Gradually add half of the sugar and continue to beat until soft peaks form. Then, add the remaining sugar and beat until stiff peaks form. The egg whites should be glossy and hold their shape.

Gently fold one-third of the whipped egg whites into the cream cheese mixture to lighten it. Then, carefully fold in the remaining egg whites in two additions, maintaining as much air as possible. This step is crucial for achieving that signature fluffy texture.

Spoon the batter into the cupcake liners, filling each about 3/4 full. Place the muffin tin into a larger baking dish and pour hot water around the tin to create a water bath. This will help the cupcakes bake gently and evenly.

Bake for 25 minutes at 320°F (160°C). Do not open the oven during baking. Once done, test with a toothpick; it should come out clean. Remove from the oven and let the cupcakes cool completely on a wire rack.

These cupcakes are best served slightly chilled or at room temperature. You can dust them with powdered sugar or drizzle a bit of fruit sauce for extra flair. The first bite should give you a soft, cloud-like sensation that melts instantly—pure bliss.