Sift all purpose flour, cornstarch, and salt 2-3 times until well combined
Whisk egg yolks with oil, milk, and vanilla
Add dry ingredients to yolk mixture and mix until smooth
In another bowl, beat egg whites with vinegar
Add sugar gradually to egg whites and beat until stiff peaks form
Mix a little beaten egg white into the yolk mixture to lighten it
Gently fold the lightened yolk mixture back into the rest of the egg whites without over-mixing
Preheat oven to 160°C
Pour batter into a lined pan
Place the pan in a larger tray filled with hot water (water bath)
Bake for 40-45 minutes or until set
Let the cake cool completely
Beat butter until pale, then add condensed milk and vanilla and beat until creamy and fluffy
Spread frosting over the cooled cake
Add grated cheese on top
