My Vanilla-Bean Marshmallows are a breeze to make - the only requirement is a good mixer since they need to whip for 15 minutes - this needs a tough motor. The alteration to this recipe is that you pour the marshmallow into a 1/2 sheet pan to create a thinner marshmallow, I would even suggest dividing the recipe in half. If you put them in a regular 9X13, it would get too thick. The marshmallow needs to rest for at least four hours before you cut them.
Lastly, to assemble you will need to prepare your chocolate:
16 oz. bittersweet chocolate
1 tsp. canola oil
In a double boiler, melt chocolate and oil together until smooth. Remove from heat, take bowl off of bain maire and let rest on counter for 15 minutes. Take a regular teaspoon and puddle 1-2 spoons onto the bottom of each graham cracker. Let those rest for 15 minutes to set up so the chocolate cools enough and then it will not flood out when you assemble.
Place a marshmallow on top of one chocolate-prepped graham cracker, then top it with another chocolate-prepped graham craker. Let rest for at least four hours to set.