Barefoot Contessa (en-US)

4 ounces bittersweet chocolate, such as Lindt
1½ tablespoons unsweetened cocoa powder, such as Pernigotti
1½ tablespoons sugar
½ cup half-and-half
1½ cups whole milk
4 tablespoons coffee liqueur, such as Kahlúa, or brewed espresso
1 teaspoon pure vanilla extract
4 cups ice
Sweetened Whipped Cream, for serving (see recipe)
Grated bittersweet chocolate, for garnish
Straws, for serving

Break the bittersweet chocolate into pieces and place it in a medium bowl set over a pot of simmering water, stirring occasionally, until just melted. Off the heat, whisk in the cocoa powder, sugar, and half-and-half and set aside

Place ¾ cup of the milk, 2 tablespoons of the coffee liqueur, ½ teaspoon of the vanilla, and half of the chocolate mixture in a blender. Add 2 cups of the ice and blend for several minutes, until the mixture is thick but not icy, like a frozen daiquiri. (You can add a little more milk or ice if it’s too thick or too thin.) Pour into two (10-ounce) ice cream soda glasses and top each with a generous dollop of whipped cream and some grated chocolate. Repeat for the second two glasses. Serve ice cold with straws and long-handled spoons.

Frozen Hot Chocolate