Preheat the oven to 325°F (163°C).
Line the round cake pan with parchment and protect the exterior with foil for the water bath.
Melt the white chocolate gently until smooth. Let cool slightly.
Mix in the cream cheese until completely smooth.
Separate the eggs.
Add the egg yolks to the cream cheese mixture and stir until combined.
Beat the egg whites in a clean bowl until stiff peaks form.
Gently fold the whipped egg whites into the cream cheese mixture in batches.
Pour into the prepared pan and smooth the surface.
Place the cake pan in a larger baking dish and add hot water around it.
Bake for 40–50 minutes, until puffed, lightly golden, and gently set.
Turn off the oven, crack the door, and leave the cheesecake inside for about 15 minutes.
Remove and cool completely.
Chill before slicing.
Dust with powdered sugar just before serving, if desired.