In a bowl, add Graham Cracker Crumbs (1 3/4 cup) and Butter (8 tablespoon). Mix well.
Press the crumbs into the bottom of a 9-inch pie pan. Place in the fridge until needed.
In a medium saucepan over medium heat, add Whole Milk (1 1/4 cup), Heavy Cream (1 cup), Milk Chocolate (7 ounce), Bittersweet Chocolate (3.5 ounce), and Granulated Sugar (3 tablespoon). Bring these to a simmer, allowing the chocolates to melt.
Mix together Corn Starch (2 tablespoon) and Water (3 tablespoon).
Once the chocolate is melted, whisk to dissolve it. Add cornstarch mixture and whisk until the mixture thickens.
Remove from the heat, then add Vanilla Extract (2 teaspoon) and Salt (1/4 teaspoon). Whisk until well-mixed.
Add the chocolate pudding to the prepared crust. Cover with plastic wrap or aluminum foil. Put it in the fridge for at least 6 hours until the pudding sets.
Once the pudding is set, spread Mini Marshmallows (3 cup) on top. Toast with a blowtorch or place under the broiler for few seconds.