Mix the vinegar with the milk and leave to stand for 5 minutes while you work on the cake batter.

Sift in the flour,baking powder and baking soda into a bowl.

In a separate bowl, using a beater, mix together the butter and lemon extract or zest of one medium lemon, until the butter is light and creamy. It should take about two minutes to get the butter to this stage.

Add in the condensed milk and beat for two more minutes.

Now add half of the flour to the condensed milk mixture and beat until incorporated.

Add ½ of the milk and vinegar mixture and beat.

Repeat once more until the rest of the flour and milk mixture is added to the condensed milk mixture. Beat until all the ingredients are just incorporated and then divide the batter into 2 greased and lined 8 inch/ 20cm cake tins.

Bake for 25 to 30 minutes at 350°F/180°C until a skewer inserted into the middle of the cake comes out clean

Remove the tins from oven and allow to cool on wire rack for 5 minutes.

Turn the cake out onto a the wire rack and allow to cool completely before frosting.

Using an electric mixer, beat the butter on medium speed until smooth.

Add in the powdered sugar and mix for 2 minutes or until the mixture starts to come together.

Add in the cream lemon extract or zest of one lemon and continue mixing on medium speed for another minute or until everything is well combined, scraping down the sides of the bowl as needed.

Frost the cake only once it has cooled completely.