Step 1

Combine milk, cocoa, syrup, chocolate pieces and vanilla in a 3- to 7-quart slow cooker. Cover and cook on Low until the chocolate is melted, about 2 hours. Stir in liqueur (if using), cream and salt. Keep warm. (Stovetop variation: Whisk milk, cocoa and syrup in a medium saucepan over medium heat. When steaming, whisk in chocolate, 1 piece at a time, until melted, 5 to 8 minutes. Add vanilla. Whisk in liqueur (if using), cream and salt. Keep warm.)

Step 2

Arrange accompaniments of your choice on a serving board, and serve with the hot chocolate.