Preheat the oven to 350 F

In a food processor or with a ziploc bag/rolling pin, grind ~2 packages of graham crackers until fine

As soon as the crackers are fine, measure out two cups. Combine 2 1/2 cups of graham cracker crumbs with melted butter, salt, and sugar. Mix until the ingredients are all incorporated.

Evenly distribute the graham cracker crust along the base of an 8” tart pan with a removable base or a pie pan. After distributing, press the mixture down with a measuring cup or other flat surface until it forms a very compact layer

Place the pans in the oven and bake for 15 minutes (or until slightly golden) and set aside to cool while you make the pudding

Set aside a bowl with a fine-mesh sieve on top. This will be to strain and cool the pastry cream once it is cooked

In another bowl, whisk together the cornstarch and sugar. Add the eggs and whisk until smooth. Set aside the mixture

In a saucepan, pour in the milk, salt, and vanilla extract. Place the mixture on medium-high heat until just under a boil. Be sure to stir the mixture so the milk solids do not stick to the bottom of the pan

When the milk is warmed, add 1/3 of the hot milk into the egg mixture, whisking constantly to ensure the eggs do not cook. After it is combined, pour the egg-milk mixture back into the remaining ⅔ of the hot milk. Whisk over medium heat until the mixture is as thick as lightly whipped cream. It should just come just barely to a boil – be sure not to let it get beyond this as the cream will curdle. Remove from the heat and immediately pour through the sieve into the bowl

Immediately add in the chocolate and mix to combine. After the chocolate is melted, add the butter one tablespoon at a time. Stir until smooth before adding the next piece of butter. Let it sit for 10 minutes to cool slightly

Pour the pastry cream directly into the graham cracker crust. Press a piece of plastic wrap onto the surface so it is touching and covering all of the custard. Chill in the fridge for at least 4 hours or ideally overnight

Use a double boiler or create one using a bowl and pan. Fill the pan with 2” warm water and place a bowl over the pan so it can heat the egg whites with the steam, but it should not touch the bottom

Add egg whites, sugar, and cream of tartar to the bowl. Place the bowl over the warm water. The pan should not touch the bottom but be heated by the steam

On low, heat the egg white mixture stirring constantly until gently warmed and the sugar is dissolved. Be very careful at this stage to not let the egg whites cook. Scrape the sides of the pan, stir constantly, and remove when sugar dissolves

Once dissolved, whip the egg whites on high until stiff peaks form. The mixture will be very glossy and thick. When you place the whisk into the eggs and pull up, it should create a peak. Once it reaches this point, add in the vanilla and mix to evenly combine.

Remove the pie from the fridge and remove the layer of plastic wrap. Top the pie with the marshmallow and toast with a blow torch (this can also be done on broil in the oven, but it will not have quite the same effect. To do this, place it on the top rack in the oven on the broil setting for ~1-3 minutes keeping a close eye so it does not burn.)