Preheat the oven to 350°F.

Crush about 2 packages of graham crackers in a food processor or with a rolling pin until fine.

Measure out 2 1/2 cups of crumbs and mix with melted butter, sugar, and salt until well combined.

Press the mixture firmly into the bottom of your cake pans to form a compact layer.

Bake for 10 minutes or until slightly golden. Set aside to cool.

In a bowl, whisk together sugar, flour, cocoa powder, baking soda, baking powder, and salt.

Add the vanilla, eggs, buttermilk, and oil, and mix until combined.

Slowly stir in the hot coffee until the batter is smooth and thin.

Pour the batter into 3 greased and floured 6" pans or 2" pans.

Bake at 350°F for about 25 minutes, until a toothpick comes out clean. Let cool.

Place chocolate, butter, salt, and vanilla in a bowl.

In a small pan, heat cream and sugar over medium heat until hot but not boiling.

Pour the hot cream mixture over the chocolate and let sit for 1 minute, then stir until smooth.

Chill in the fridge until cool but not hard.

Set up a double boiler with a bowl over a pan of about 1 inch of simmering water.

Add egg whites, sugar, and cream of tartar to the bowl. Stir constantly over low heat until the sugar dissolves and the mixture is warm.

Remove from heat, add vanilla, and whip on high until stiff peaks form and the mixture is glossy.

Place a cake layer with graham cracker crust on the bottom.

Pipe a ring of ganache around the edge and fill the center with marshmallow cream.

Repeat with the second layer.

Cover the entire cake with chocolate ganache.

Optionally, top with marshmallows and toast them for extra decoration.