- Dough Preparation: In a stand mixer, combine lukewarm milk, lukewarm water, instant yeast, granulated sugar, and all-purpose flour. Add melted unsalted butter and salt. Mix until well combined. Switch to the hook attachment and knead for 6-8 minutes until the dough is smooth and elastic. Cover and let it rest for 15 minutes to rise slightly.
- Filling Preparation: In a saucepan over low-medium heat, whisk together cocoa powder, heavy whipping cream, semi-sweet chocolate chips, and granulated sugar. Add melted unsalted butter, vanilla extract, and a pinch of salt. Stir until smooth and well combined, then remove from heat. Allow the filling to cool slightly before mixing in the graham cracker crumbs.
- Assembly: On a lightly floured surface, roll the risen dough into a 10” x 16” rectangle. Brush with melted butter, then spread the cooled filling evenly over the dough, leaving edges clear. Sprinkle additional graham cracker crumbs on top. Roll the dough tightly from one end into a log, then slice it into 8-10 pieces. Arrange the rolls side by side in a greased baking pan.
Baking: Preheat your oven to 350°F (175°C). Bake the rolls for 25-28 minutes or until they turn golden brown. Remove from oven and cool in the pan for 10 minutes before proceeding to the topping.
- Meringue Topping: Using a double boiler, gently heat egg whites and granulated sugar while whisking continuously until the mixture is warm and the sugar dissolves. Transfer the mixture to a stand mixer and beat on high speed until stiff peaks form. Add cream of tartar, salt, and vanilla extract during beating to stabilize the meringue.
- Finalizing Rolls: Spread the meringue evenly over the cooled rolls. Use a kitchen torch or place the pan under the broiler briefly to toast the meringue until it turns a golden brown hue. Serve warm for the best gooey experience.