Add heavy whipping cream, powdered sugar, and vanilla extract to a bowl. Beat until soft peaks form. Keep chilled.
In another bowl, whisk chocolate pudding mix with cold milk until smooth and thick. Let it set for five minutes.
In a separate bowl, fold marshmallow fluff into half of the whipped cream until smooth and fluffy.
Arrange graham crackers in a single layer at the bottom of a baking dish, breaking pieces to fit.
Spread a layer of marshmallow cream evenly over the crackers.
Add a layer of chocolate pudding and spread gently.
Sprinkle chocolate chips and mini marshmallows over the pudding.
Repeat the layers of graham crackers, marshmallow cream, pudding, and toppings until all ingredients are used.
Finish with whipped cream on top and garnish with remaining chocolate chips and marshmallows.
Cover and refrigerate for at least six hours or overnight.
Slice and serve chilled.