01 -
Set oven temperature as noted on box instructions. Grease a 9x13 pan and prepare the cake mix as directed, stirring in vanilla.
02 -
Bake using the timing on the package. Set aside for 10 minutes to cool.
03 -
Take a wooden spoon and make evenly spaced holes about 1 inch apart on the whole cake.
04 -
Squeeze marshmallow fluff into the holes using a piping bag or a baggie with the corner snipped.
05 -
Stir the cocoa powder into Cool Whip until it's mixed thoroughly.
06 -
Spread the whipped topping mixture across the cake, toss marshmallows on top, and drizzle with chocolate syrup.
07 -
Wrap tightly and chill for at least 6 hours or leave it in the fridge overnight.