Preheat oven & prepare pan: Preheat oven to 320°F (160°C). Line an 8-inch round cake pan with parchment paper. Wrap the outside with foil to prevent water from leaking during the water bath.
Make the cream cheese mixture:
In a heatproof bowl over simmering water, melt cream cheese, butter, and milk until smooth. Let it cool slightly.
Beat in egg yolks and vanilla extract until combined.
Sift in flour and cornstarch, gently folding to combine without overmixing.
Whip the egg whites:
In a clean bowl, beat egg whites with cream of tartar (or salt) until foamy.
Gradually add half of the sugar and beat until soft peaks form. Then add the remaining sugar and beat until stiff peaks form.
Fold together:
Gently fold one-third of the egg whites into the cream cheese mixture to lighten it.
Carefully fold in the remaining egg whites until just combined. Do not deflate the batter.
Bake in a water bath:
Pour the batter into the prepared pan.
Place the pan in a larger baking dish and add hot water until it reaches halfway up the sides of the cake pan.
Bake for 50–60 minutes, or until the top is golden and a skewer comes out clean.
Cool gradually:
Turn off the oven and leave the cheesecake inside with the door slightly open for 15–20 minutes.
Remove from the oven, cool to room temperature, then refrigerate for at least 2–3 hours before serving.
Serve:
Dust with powdered sugar if desired. Slice and enjoy the airy, melt-in-your-mouth texture.
✨ Tip: For extra height and fluffiness, make sure the egg whites are beaten to stiff peaks and fold gently. You can also add a few drops of lemon juice to the egg whites to stabilize them further.
If you want, I can also give you a super simple 4-ingredient Japanese cheesecake version that’s much faster and just as soft and fluffy.
