Take a deep pan on medium flame. Add Milk and Sugar together.

Stir continuously. It will give big big bubbles. Keep stirring.

Keep stirring till it get half and change the colour. Once the bubbles get small and milk get thicker.

Off the gas and add baking soda. Stir it continuously till it gets light and fluffy.

Condensed Milk is ready. You can add it in making cake, sweets etc. If condensed milk becomes thicker add warm milk to to get your consistency.