Preheat the oven to 300°F (150°C) and line a 6-inch round baking pan with parchment paper.

Melt cream cheese and unsalted butter in a double boiler. Stir in milk until smooth.

Whisk in egg yolks and vanilla extract.

Sift together cake flour and cornstarch into the cream cheese mixture. Stir until no lumps remain.

Beat egg whites and lemon juice until frothy. Add granulated sugar until medium-soft peaks form.

Fold one-third of the meringue into the batter, then gently fold in the remaining meringue.

Pour the batter into the prepared pan, place it in a larger tray filled with hot water.

Bake for 30 minutes at 300°F (150°C), then reduce to 230°F (110°C) for 30 minutes, and finally increase to 275°F (135°C) for 13-15 minutes.

Cool in the oven for 15 minutes, then remove from the water bath and cool completely on a wire rack.

Dust with powdered sugar before serving; slice carefully to preserve texture.