Put cocoa powder, milk in a blender and blend until smooth.
Heat a deep nonstick saucepan on low flame. Add sugar, cocoa powder and milk mixture.
Cook it over medium-low heat for 10 minutes until it starts to thicken while stirring constantly.
Now add butter and mix well.
Remove from the heat. Stir in salt and vanilla extract.

Let cool completely and skim off any skin that may have formed.
Pour into a clean/sterile bottle with a spout and store covered in the refrigerator.
A yummy delicious chocolate syrup is ready to enjoy.

Tips:

Brown sugar can be replaced with white sugar.
Cook on the low medium heat.
Don’t overcook s the syrup it will get thicker as it cools.