Preheat oven to 325 degrees Fahrenheit.

In a large bowl, combine graham cracker crumbs, sugar, and salt. Stir in melted butter until well combined.

Press the crumb mixture into a 9-inch deep dish pie pan, evenly spreading the mixture on the bottom and up the sides.

Bake for 8-10 minutes, then remove and set aside to cool.

In a medium saucepan, whisk together cornstarch, sugar, and salt. Add egg yolks, milk, and heavy cream; whisk until smooth.

Cook over medium heat, whisking constantly until mixture thickens and begins to bubble.

Remove from heat and stir in chopped chocolate, butter, and vanilla extract until smooth.

Pour filling into the cooled crust. Chill in refrigerator for 5-6 hours until set.

Preheat oven to 350 degrees Fahrenheit for marshmallow topping.

Arrange halved regular-sized marshmallows around the top, then fill in with mini marshmallows.

Bake for 3-4 minutes until marshmallows puff up, then broil on low for 2-4 minutes to toast, if desired.

Serve warm or cooled. The pie can be stored in the refrigerator, but marshmallows may be sticky.