Pour the milk in a pan and add the sugar.

Bring to a boil and then simmer on a medium-high flame, stirring regularly. It needs to reduce by half its volume.  This should take about 20 minutes.  The milk can boil over anytime, so keep watching it.

After about 17-18 minutes, the milk will turn a very vibrant color and the texture will be very frothy.

Switch off the flame and add the baking soda. Stir well and let it cool.

Once cooled, stir well and store in an air tight container or use immediately.