Step 1

Bake the cake in a 9 x 13 inches dish according to directions listed on the box.

Step 2

When the cake is baked, using the handle of a wooden spoon poke the cake, making the holes about an inch apart. Do not poke it all the way to the bottom just about 2/3 of the height.

Step 3

Place 2 cups of marshmallow fluff in a microwave-safe bowl and add 2 Tablespoons water.  Microwave in a 20-seconds interval and stir until smooth. You can pour it from a jug or place it in a zip-lock bag and cut off the corner, then pipe it into the holes. Spread remaining on top. Place in the fridge.

Step 4

Next, place chocolate chips sweetened condensed milk, and 2 Tablespoons of heavy cream in a microwave-safe bowl and heat in 20-second intervals, stirring until smooth. Spread over the cake and chill until the chocolate is cooled completely.

Step 5

Beat 2 cups of heavy whipping cream with vanilla and instant hot chocolate mix until stiff peaks form. Spread over the chilled cake and garnish with mini marshmallows.

Step 6

Drizzle with chocolate fudge sauce before serving, if desired.