Anise adds a distinctive note to this pairing of coffee and chocolate.
In a 3-qt. slow cooker, combine the coffee, sugar, chocolate syrup, and anise extract.
Place cinnamon sticks and cloves in a double thickness of cheesecloth; bring up corners of cloth and tie with string to form a bag. Add to slow cooker. Cover and cook on low for 2-3 hours.
Discard spice bag. Ladle coffee into mugs; garnish each with a cinnamon stick if desired.