Place the chocolate and sweetened condensed milk in a microwave safe bowl
Microwave for 30 seconds, stir, and microwave again for 30 seconds
Stir until all the chocolate is melted
Cover and place in the fridge for about 2 hours
Scoop the hardened mixture into a large mixing bowl
Beat on HIGH for at least 5 minutes, scraping the sides of the bowl several times
Continue beating until the mixture is light and airy and transforms from fudge to frosting
Use to frost a cake, top cupcakes, spread on graham crackers, or serve as desired
