There's no better treat after sledding or ice skating than homemade hot cocoa.
Combine chocolate and milk in a large saucepan over medium heat. Whisk until chocolate is melted and milk is very hot and frothy, about 20 minutes.
Remove from heat. Add vanilla; pour into a blender, filling halfway. Blend, holding lid in place (the hot liquid will expand), until frothy. serve immediately; blend remaining milk-and-chocolate mixture.