- Prep the Water Bath and Oven: Preheat your oven to 150 degrees Celsius (300 degrees Fahrenheit). Line a deep 6-inch cake pan with parchment paper on the bottom and sides.
- Whisk the Base: In a large bowl, whisk together the softened cream cheese, melted butter, milk, egg yolks, and vanilla extract until smooth and completely free of lumps. Sift in the cornstarch and whisk gently until combined.
- Whip the Meringue: In a separate clean, oil-free bowl, whip the egg whites with the lemon juice until foamy. Gradually add the granulated sugar while whipping continuously on medium-high speed until glossy, soft peaks form.
- Fold Carefully: Gently fold one-third of the meringue into the cream cheese batter using a silicone spatula. Add the rest of the meringue in two stages, folding delicately in a circular motion to avoid deflating the trapped air bubbles.
- Bake in Water Bath: Pour the velvety smooth batter into the prepared pan and tap it lightly on the counter to release large air bubbles. Place the cake pan inside a larger baking dish filled with hot water (about 1 inch deep). Bake at 150 degrees Celsius for 50 to 55 minutes until golden on top and set in the middle.
- Cool Slowly: Turn off the oven, prop the door open slightly, and let the cake cool inside for 15 minutes to prevent sudden deflating. Transfer to a rack, dust with powdered sugar, and serve warm or chilled.
The Secret Physics Behind a Cloud Cake
The extraordinary texture of a Cloud Cake relies on mechanical aeration rather than chemical leaveners like baking powder. When you whip egg whites with sugar, the proteins denature and create a stable matrix that traps tiny air pockets.
Baking in a hot water bath (bain-marie) ensures gentle, indirect heating. This uniform temperature distribution keeps the delicate egg protein matrix intact while preventing the outer crust from expanding faster than the moist interior. The cornstarch acts as a structural stabilizer, binding free moisture so the texture stays airy rather than soggy…..
