Mix graham cracker crumbs, melted butter, 1 tbsp sugar, and salt. Toast on a baking sheet at 350°F for 8 minutes. Let cool.

In a saucepan, whisk remaining sugar, cocoa powder, and cornstarch. Gradually whisk in milk and heavy cream until smooth.

Cook over medium heat, whisking constantly, until boiling and thickened. Boil 1 minute, then remove from heat.

Slowly whisk 1/2 cup of the hot pudding into the beaten egg yolks to temper them. Return egg mixture to the saucepan.

Cook for 1-2 more minutes over medium-low heat until very thick. Remove from heat and stir in chopped chocolate and vanilla until smooth.

Transfer pudding to a bowl, press plastic wrap to the surface, and chill for at least 3 hours.

Assemble parfaits in glasses: layer graham crumbs, chocolate pudding, and marshmallow creme. Repeat layers.

Top each glass with a large marshmallow. Use a kitchen torch to toast the marshmallow until charred and gooey. Serve immediately.