In a stand mixer, combine ½ cup lukewarm milk and ½ cup lukewarm water with 2 ¼ teaspoons instant yeast and 2 tablespoons granulated sugar. Gradually add 3 cups all-purpose flour, ¼ cup melted unsalted butter, and 1 teaspoon salt. Knead on low speed for 6–8 minutes until smooth and elastic. Cover and let rise for about 15 minutes.

In a saucepan over low-medium heat, whisk together ½ cup unsweetened cocoa powder, ½ cup heavy whipping cream, and ½ cup semi-sweet chocolate chips until melted and smooth. Stir in 2 tablespoons of granulated sugar, 2 tablespoons melted butter, and 1 teaspoon vanilla extract. Mix in ½ cup graham cracker crumbs and let cool.

On a floured surface, roll dough into a 10” x 16” rectangle, ¼ inch thick. Brush with 2 tablespoons melted butter, then spread cooled filling evenly. Sprinkle ½ cup of graham cracker crumbs, tightly roll from long side, and slice into 8–10 pieces.

Preheat oven to 350°F (175°C). Bake rolls for 25–28 minutes or until golden brown. Let cool in pan for 10 minutes.

In a double boiler, whisk together 3 egg whites and ¾ cup sugar until warm. Transfer to a stand mixer and beat until stiff peaks form. Add ¼ teaspoon cream of tartar and 1 teaspoon vanilla extract, continuing to beat until glossy.

Spread meringue on cooled rolls and toast lightly with a kitchen torch or broiler. Serve warm.