In a large bowl, whisk the cream cheese until smooth, then slowly add milk, melted butter, egg yolk, yogurt, lemon juice, brandy, stirring until evenly combined. Then add cake flour and corn startch, whisking to make sure there are no lumps.
Step 3: Egg white mixture
In another large bowl, add the egg whites , sugar, and cream of tartar, and beat until you see hard peaks when lifting the mixer up.
Take about ¼ of the egg whites and fold them into the egg yolk mixture, then repeat with the remaining egg whites until the batter is evenly combined.
Grease 6″ cake pan with butter, line bottom and around the edge with baking paper.
Pour the batter into the parchment-lined pan and shake to release any large air bubbles.
Fill the larger pan about 1-inch (2-cm) with hot water. Bake with water bath in a preheated 375°F/190°C for 45 mins.
Remove from the oven, and carefully invert the cake onto your hand and peel off the paper. Be extremely careful, the cake will be hot. You can also invert the cake onto a plate, but this will cause the cake to deflate more.
Optional: sprinkle the top of the cake with powdered sugar, slice, and serve!