Melt chocolate chips over double broiler. If you don’t have a double broiler, melt in microwave (using a glass bowl) in 30 second increments at 50% power until the chocolate has melted completely.
Stir in sweetened condensed milk.
Add the butter flavor Crisco to melted chocolate and sweetened condensed milk mixture. *Optional—you don’t have to add this, but I have found that it will give your fudge a nice shine and prevent it from turning white, or blooming.