Put all the dry ingredients (milk powder, powdered sugar, cornflour, soda) and mix it well.
Now add melted butter and mix it well again.
Add ½ cup of water and mix it well till no lumps.
Take a pan, put the mixture and cook it for 1 to 2 minutes on medium flame. Do not cook for longer time otherwise, it will get very thick when cool down.
After 2 minutes, switch off the flame and keep the mixture cool down for some time.
Once cooled, condensed milk will become slightly thick.
Now put condense milk in an airtight container and store it in the fridge for 10 to 15 days.