Preheat your oven to 325°F (165°C).

Line a 12-cup muffin tin with parchment paper liners.

Place a large baking dish in the oven. You will fill it with hot water for a water bath.

In a heatproof bowl, combine cream cheese, butter, and milk. Set it over a pot of simmering water and whisk until smooth.

Remove from heat and whisk in sugar until dissolved.

Add lemon juice and vanilla extract.

Whisk in egg yolks one at a time.

Sift cake flour and salt over the mixture and fold gently until combined.

Prepare the Meringue:

In a clean bowl, beat egg whites on low until foamy.

Add cream of tartar and increase speed to medium.

Gradually add sugar, beating until firm, glossy peaks form.

Fold a quarter of the meringue into the cream cheese mixture to lighten it.

Gently fold in the remaining meringue in two additions.

Pour batter into muffin cups, filling each about 3/4 full.

Place the muffin tin into the baking dish and add hot water until it reaches halfway up the sides of the tin.

Bake for 18-20 minutes until the tops are lightly golden and the centers jiggle slightly.

Turn off the oven, crack the door open, and let the cheesecakes cool for 15 minutes.

Remove from oven and cool completely before serving.