Instructions
In a small bowl, mix cocoa powder and sugar. Set aside.
In a heavy saucepan, heat milk, butter and corn syrup over medium heat until butter is melted.
Over medium heat, whisk 1/2 of the dry ingredients into the milk mixture until smooth. Repeat with the remaining 1/2 of the dry ingredients.
Bring mixture to a boil, then reduce heat to a simmer, stirring constantly for 1-1/2 minutes.
Remove the saucepan from heat and stir in the vanilla.
Serve warm or store in refrigerator in a tightly covered container for up to 7 days.
Notes
For this recipe I used regular half and half and dark cocoa powder.