Combine all of the ingredients in a saucepan over low heat. Stir constantly until the chocolate melts, the sugar dissolves, and the beverage reaches desired temperature. Do not let the mixture boil.
Pour into a mugs and garnish with desired toppings.
Notes
Choose a high-quality dark or semisweet chocolate for the best, rich flavor. I like Lindt 78% dark chocolate. Chocolate chips will also work!
Adjust the amount of sugar to suit your taste. If you want a less-sweet hot chocolate, cut the sugar in half. If your kids like a sweeter drink, add more sugar.