Place brown sugar, caramel sauce, milk and coffee in the crockpot. Add in the espresso powder, if using.
Set the crockpot to low for 2 hours, or high for 45 minutes.
Stir in the vanilla before ladling out to serve.
Garnish with whipped cream and extra caramel syrup, as desired.
Storage: Store it in an airtight container, and it will last for up to four days in the refrigerator. Reheat it in the microwave or in a saucepan. alternatively, drink it over ice for a special treat.This recipe serves 6 but you can double or triple the recipe with no problem to serve a larger crowd.