Combine cocoa powder & water in a saucepan over medium heat.
Whisk until smooth & thick.
Add in sugar, corn syrup & salt. Continue to cook & whisk for a few minutes, until mixture comes to a light boil.
Remove from heat and stir in vanilla.
Store refrigerated in sealed jar.
For chocolate milk - add 2-3 tablespoons (to taste) to a glass of milk.
Notes
*I recommend regular cocoa powder. I tried Dutch processed - it's just not as good.**You may omit the corn syrup and use 1 cup sugar total. The corn syrup version was preferred.