1. Preheat oven to 350°F (175°C). Crush graham crackers into fine crumbs. In a bowl, combine crumbs, ¼ cup sugar, and ½ teaspoon salt. Add 6 tablespoons melted butter; mix until moistened. Press firmly into a 9-inch pie plate. Bake for 10-12 minutes until golden. Cool completely.

2. Place chopped chocolate in a heatproof bowl. In a saucepan, combine heavy cream and 2 tablespoons unsalted butter; heat until just simmering. Pour hot cream over chocolate, let sit 5 minutes, then whisk until smooth. Stir in 1 teaspoon vanilla extract and a pinch of salt. Pour filling into the cooled crust. Chill for 2-3 hours until firm.

3. In a heavy-bottomed saucepan, combine ¾ cup sugar, ¼ cup water, and ¼ cup light corn syrup. Heat over medium-high until sugar dissolves, then boil to 240°F (116°C). In a stand mixer, whip 2 egg whites and ¼ teaspoon cream of tartar until soft peaks form. Slowly pour hot syrup into egg whites while whipping on medium-high. Continue whipping on high for 10-15 minutes until thick, glossy, stiff peaks form and bowl is cool. Gently fold in 1 teaspoon vanilla extract.

4. Retrieve chilled pie. Generously dollop and spread marshmallow topping over the chocolate layer, creating swirls. Torch marshmallow with a kitchen torch until golden brown and charred (or broil for 1-2 minutes). Serve immediately; run knife under hot water for clean slices.