Preheat your oven to 320°F (160°C). Prepare a 12-cup muffin tin with liners or grease lightly.

Melt cream cheese, butter, and milk in a saucepan over low heat until smooth. Remove from heat, cool slightly, then whisk in lemon juice and vanilla.

In a bowl, whisk together flour, cornstarch, and salt until mixed. Set it aside.

In another bowl, whisk egg yolks with sugar until pale and creamy. Mix in the cooled cream cheese mixture.

Sift flour mixture into egg yolk mixture and fold gently to avoid overmixing.

Whip egg whites until soft peaks form. Gradually add remaining sugar and beat to stiff peaks.

Gently fold whipped egg whites into the batter in thirds.

Fill muffin tin cups ¾ full with batter. Tap gently on the counter and bake for 20–25 minutes until golden and set.

Allow cupcakes to cool in the tin for 5 minutes, then transfer to a wire rack. Dust with powdered sugar to serve.