Make the graham cracker crust

1. Preheat the oven to 350 degrees. Line an 8×8 baking dish with parchment paper. Set aside.
2. In a medium bowl, combine the melted butter, graham cracker crumbs, 1/4 cup granulated sugar, and 1/4 teaspoon kosher salt. Stir to combine thoroughly.
3. Transfer the graham cracker crumb mixture to the 8×8 baking dish. Spread the crumbs, so they cover the surface of the bottom of the pan. Firmly press the crumbs down, forming a compact layer.
4. Bake for 8-10 minutes, until crust is slightly golden and fragrant. Remove from the oven and set aside, allowing the crust to cool completely.

Once the graham cracker crust is completely cooled, make the homemade marshmallow

1. In the mixing bowl of your stand mixer, add the gelatin and 1/3 cup water. Stir to combine and set aside.
2. In a medium pot fitted with a candy thermometer, combine the remaining 1 cup granulated sugar, 1/4 teaspoon kosher salt, corn syrup, and 1/3 cup water, whisking to combine. Heat the mixture over medium high heat, stirring occasionally, for about 7 minutes, until the candy thermometer reaches 240 degrees.
3. Carefully transfer the hot sugar mixture into the stand mixer mixing bowl with the gelatin. Beat, using the whisk attachment of your stand mixer, on high.
4. The mixture will gradually become opaque and beautifully glossy. Add in the vanilla beans and continue to mix, until the mixture forms soft peaks and gently pulls strands away from the side of the bowl as it mixes. This will take a little bit of time – about 10-15 minutes!
5. Using a nonstick spatula, transfer the marshmallow to the pan, on top of the graham cracker crust. Use the spatula to spread the marshmallow into a smooth layer.
6. Rest uncovered for 8 hours, or overnight, so the marshmallow sets & dries.

Top with salted dark chocolate ganache

1. Melt dark chocolate in the cream with the remaining 1/2 teaspoon of kosher salt in the microwave, heating in 30 second intervals and mixing thoroughly between each interval. Once the chocolate is completely melted, continue to stir for an additional minute or two so the chocolate takes on a beautiful sheen. The texture should be glossy and smooth.
2. Pour the chocolate ganache over the top of the marshmallow layer, forming a uniform chocolate layer, about 1/4 inch thick.
3. Rest for another 4 hours, or up to overnight, so chocolate sets completely.

Once the chocolate sets, cut the bars

1. Lift the bars (using the parchment paper) out of the pan. Gently pull the parchment away from the bars. The marshmallow will stick, but you can use your fingers or a sharp knife to help pull it away from the parchment. Once you get a small part of the marshmallow to unstick, the rest should pull away relatively easily.
2. Using a sharp knife, cut into 16 bars. Enjoy!