Preheat the oven to 160°C (320°F).
Prepare the baking pan with parchment paper.
Melt the cream cheese and butter together in a double boiler.
Add milk, sugar, and lemon juice to the melted mixture, whisking until combined.
Remove the mixture from heat and let it cool slightly before adding the egg yolks.
Whisk in the egg yolks and flour until smooth.
In a separate bowl, whip the egg whites with cream of tartar until stiff peaks form.
Gently fold the egg whites into the cream cheese mixture in three additions.
Pour the batter into the prepared pan and smooth the surface.
Bake in a water bath for about 50-60 minutes, or until set.
Turn off the oven and let the cheesecake cool inside for 30 minutes.
Remove from the oven and let it cool completely at room temperature.
Refrigerate for at least 4 hours, preferably overnight.
Serve with a dusting of powdered sugar or fresh fruit, if desired.
