Pour milk to a thick bottomed and wide sauce pan over medium-high heat. Wide sauce pan will help to reduce the milk faster. Add the sugar in.
Allow milk to come to a boil. Whisk or keep stirring with a spatula at frequent intervals to avoid milk from sticking to the bottom of pan. After first boil, reduce the flame to medium for 2-3 minutes and stir continuously, so that the milk doesn't boil over.
Now you can turn the flame to med-high again. But take care to stir this mix continuously, so it doesn't stick to the bottom of your pan or doesn't boil over at any point of time.
Never walk away from the pan and if you notice the milk is boiling a bit too much or is starting to stick to the bottom of pan, reduce the flame and continue to stir.
Idea is to allow the milk to boil continuously till it thickens. Milk should continuously be boiling and bubbling. This process will take about 15-25 minutes. Milk will be fairly thick after 15-17 minutes of time has passed (Mine takes about 20 minutes).
Switch the flame off once milk has thickened and add a pinch of baking soda to it.
Keep stirring in intervals as the milk is cooling. This will prevent the prepared milk from forming a layer on top.
Allow it to cool down to room temperature. Milk will thicken a bit more as it cools. Store in a clean jar!
