Brew 2 oz of coffee (about 8 tbsp ground coffee) with 30 oz of water (to water level 6 on most drip coffee makers).

In a 3 quart pitcher, add cocoa powder, and 1/4 cup of the hot coffee. Whisk to make a thin paste, then add the rest of the coffee and whisk to incorporate the cocoa powder. Add the vanilla. Chill for at least 8 hours.

To cold coffee mixture, add the Hershey's syrup and cream and whisk to combine.

Fill a 16 oz cup with crushed ice. Pour 5 oz of the mocha mixture over the ice; it will fill it to the top.

Refrigerate leftover mocha mixture. Stir each time before pouring.