Line a 9 inch square pan with two large pieces of parchment paper, creating a sling for easy removal.

In the bowl of a stand mixer fitted with the paddle attachment, cream the butter until smooth, then add the powdered sugar, vanilla, and salt and beat for 2 more minutes.

Add in the flour and graham cracker crumbs, and mix until just combined.

Add the dough to the prepared pan and use another piece of parchment paper to press it into an even layer. Use the back of a spoon or small measuring cup to pack it in and level it out. Place in the fridge to chill for 30 minutes.

While the base is chilling, preheat the oven to 325 degrees F.

Bake the shortbread for 30-35 minutes or until it is an even light golden brown.

Allow to cool for a few minutes at room temperature, then place in the fridge while you make the chocolate ganache layer.

Chop the chocolate and add to a medium bowl. Set aside.

In a small saucepan, heat the heavy cream over low heat and bring to a simmer or about 190 degrees F.

Pour the hot heavy cream over the chocolate, place a plate on top of the bowl, and allow to sit for a couple minutes.

Remove the plate and gently stir with a rubber spatula until the ganache is smooth. Alternatively, you can use an immersion blender.

Pour the ganache over the cooled crust, and use an offset spatula to spread into an even layer.

Liberally grease the parchment above the ganache with softened butter. Place in the fridge while you make the marshmallow layer.

In the bowl of a stand mixer fitted with a whisk attachment, add 113g (½ cup) of water and sprinkle the gelatin on top in an even layer. Set aside to bloom.

In a large saucepan, combine the other 113g (½ cup) of water, granulated sugar, light corn syrup, and salt.

Heat the saucepan over medium heat, stirring frequently until the sugar dissolves. Raise the heat to medium-high, and without stirring, bring it to 240 degrees F.

While the mixer is on low speed, slowly drizzle the hot sugar over the gelatin.

Once all of the hot sugar is poured in, increase the mixer speed to high and mix until thick and cool (about 100 degrees F). Add the vanilla paste while it is mixing.

Pour the marshmallow mixture on top of the ganache layer. Tap the pan on the counter a few times to release any air bubbles.

Sprinkle a small amount of powdered sugar on top, and cover with plastic wrap. Allow to set at room temperature for at least four hours or overnight.

Once set, use a sharp, buttered knife to cut the bars into 16 squares. Use a kitchen torch to toast the tops of the marshmallows. Enjoy!