Grease well a 24cm spring-form cake pan. Beat butter and cream cheese with an electric blender until well combined. Drip in milk gradually and beat until mixture is smooth. Leave aside.
Add in egg yolk and lemon juice, and beat until light and fluffy. Fold in sifted flour and corn flour to mix until evenly blended.
In a clean bowl, whisk egg whites with salt and sugar until thick. Gradually fold into the cream cheese mixture. Pour mixture into the prepared pan and bake in preheated oven at 160°C for 11 ¼ hours or until slightly golden.
Switch off the oven and leave cake inside the oven for 1215 minutes with oven door ajar.
Remove cake and invert the cake for 56 minutes before turning it out onto a wire rack to cool completely.