Begin by pouring the whole milk and heavy cream into a medium saucepan. Place the saucepan over medium heat and warm the mixture until it starts to steam, taking care not to let it boil.
Once the dairy mixture is steaming, add the semi-sweet chocolate chips and unsweetened cocoa powder. Use a whisk to combine, stirring continuously until the chocolate chips are completely melted and the cocoa is evenly mixed in.
Next, stir in the sugar and vanilla extract, ensuring everything is well blended. Taste the hot chocolate and adjust the sweetness as desired, continuing to heat it for a few more minutes until it's very hot, without it reaching a boil.
After heating, remove the saucepan from the heat source. Carefully pour the luscious hot chocolate into a large serving bowl or distribute it into individual mugs for a personal touch.
To create your hot chocolate bar, elegantly arrange an array of toppings in small bowls or jars, making them easily accessible for your guests. Include a delightful selection: whipped cream, mini marshmallows, crushed peppermint candies, chocolate shavings, cinnamon sticks, caramel sauce, ground nutmeg, and colorful sprinkles.
Serve the hot chocolate alongside the toppings, encouraging your guests to personalize their cups with their favorite selections for a festive experience.