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.
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!
Use 2% milk (or even whole milk or cream) for the smoothest, creamiest flavor and texture.
Warm the hot chocolate over low heat -- do not let it boil -- and whisk frequently to help the ingredients dissolve and combine.
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.