1) grate, shave the chocolate…this can be done with a cheese grater, using the fine side!
2) place the shavings into a cup. make sure theres lots, you want a rich cup of hot chocolate!
3) Now, add some boiling milk to this cup, pour the milk right onto the chocolate!
4) stir together quickly, and it should all be good.
5) drink it!=)

yummmm!
References :

2 1/2 cups whole milk
2 cups half-and-half
4 ounces bittersweet chocolate, chopped
4 ounces milk chocolate, chopped
1 tablespoon sugar
1 teaspoon pure vanilla extract
1 teaspoon instant espresso or coffee powder
4 to 5 vanilla beans or cinnamon sticks, for garnish

Heat the milk and half-and-half in a saucepan on medium heat to just below the simmering point. Remove the pan from the heat and add both chocolates. When the chocolates are melted, add the sugar, vanilla extract, and espresso and whisk vigorously. Reheat gently and serve immediately. Use a vanilla bean or cinnamon stick to garnish each serving.
———————————————————————————

For a healthier version
Hot Chocolate

1 cup lowfat milk
1 cinnamon stick
2 teaspoons unsweetened cocoa powder
2 teaspoons sugar
2 teaspoons water
1/4 teaspoon pure vanilla extract
Dark chocolate, as a garnish

Heat the milk and the cinnamon stick until just simmering. In a mug, combine the cocoa powder, sugar and water and stir to make a paste. Remove the cinnamon stick from the milk. Pour the milk into the mug and stir to mix well. Add the vanilla extract and stir. Grate a little dark chocolate on top for garnish.
References :
http://www.foodnetwork.com