FOR THE CAKE
1 14-oz. can sweetened condensed milk
1 cup semisweet chocolate chips, melted
Butter, for greasing
Flour, for pan
1 box chocolate cake mix, plus ingredients called for on box
Chocolate shavings, for garnish
FOR THE FROSTING
1 cup butter, softened
2 1/2 cups powdered sugar
3/4 cup cocoa powder
2 teaspoons pure vanilla extract
pinch of salt
1/4 cup heavy cream (plus more if necessary)
Preheat oven to 350F
Butter and flour a 9×13 pan.
Bake the chocolate cake mix according to package directions
Poke cake all over with the bottom of a wooden spoon.
In a bowl, mix together condensed milk and melted chocolate until combined fully.
Pour this mixture into the holes on the cake.
In a large bowl and using a hand mixer, beat the butter, powdered sugar, cocoa powder, vanilla, and salt until fully incorporated
Gradually add in the heavy cream ONLY adding tablespoon by tablespoon until consistency is creamy but can still hold peaks
Spread the frosting all over cake
Sprinkle with chocolate shavings.
Source : thecozycook.com