GRAHAM CRACKER CRUST:
5 whole graham crackers
2 tablespoons melted butter or margarine
3 cups whole milk
2 large egg yolks
1/2 cup sugar
1/4 cup cornstarch
1/4 teaspoon fine salt
4 ounces semisweet chocolate, coarsely chopped
1 ounce unsweetened chocolate
2 tablespoons unsalted butter
1 1/2 teaspoons pure vanilla extract
50 miniature marshmallows
2 graham crackers, broken into large pieces
Special equipment: Six 5-ounce jars and a kitchen torch or broiler
For the graham cracker crust: Pulse graham crackers and butter in a food processor until crushed into crumbs. Add 2 tablespoons of graham cracker crumbs to each of six 5-ounce jars. Press the crumbs down to the bottoms with the back of a spoon. Reserve the remaining graham cracker crumbs.
For the pudding: Heat the milk until hot but not boiling in a saucepan on the stove or in a heat-proof bowl in the microwave (1 minute on high). Beat the egg yolks in a medium bowl and add the hot milk, slowly at first, stirring constantly so the eggs do not scramble. Continue until all the milk is incorporated.
Add the sugar, cornstarch and salt to a medium saucepan. Whisk until there are no lumps. Slowly whisk in the hot milk mixture in a steady stream so lumps do not form. Cook over medium-low heat, stirring constantly, until the mixture starts to bubble and has thickened, about 10 minutes. Add the semisweet and unsweetened chocolate and stir until the chocolate is melted, about 2 minutes. Remove from the heat and stir in the butter and vanilla extract. Distribute the pudding among the jars and refrigerate until fully set, 2 to 3 hours.
For the toppings:
Remove the jars from the refrigerator 2 hours before serving to come to room temperature. Just before serving, top the pudding with another layer of the reserved graham cracker crumbs. Add the miniature marshmallows to cover. Use a kitchen torch to brown the marshmallows (or carefully place under the broiler for 15-30 seconds). Top each S'mores in a Jar with a large piece of graham cracker.