Preheat oven to 175°C.
Grease and line the cake tins.
In a bowl whisk together maida, baking powder and baking soda.
In another bowl take butter and vanilla and beat for 2 minutes.
Add in the condensed milk and beat for one more minute.
In the condensed milk tin, add milk and vinegar. With a spoon scrap all the remaining condensed milk so that it mixes with the milk. The milk will curdle in five minutes.
Now add 1/3rd of the flour to the butter mixture and beat until incorporated.
Add 1/2 of the curdled milk mixture and beat. Repeat again finishing with the third portion of flour.
Stop beating once all the ingredients are incorporated.
Pour the batter into prepared cake tins.
Bake for 30-35 minutes if 6" tin, 40-45 minutes if it is 7/8" tin and 25-30 minutes if baking in a tray.
Insert a skewer stick and check if the batter clings to it or it comes out clean.
If clean, remove the tins from oven and allow to cool on wire rack for 5 minutes.
Flip the cake on the wire rack and remove the lining paper.
Allow it to cool completely.
Wrap with layers of cling film and refrigerate until needed.
