Begin by making the dough using a perfect pie dough recipe, substituting in the graham cracker crumbs. Once the dough is ready, form it into two balls and flatten slightly into discs. Wrap in plastic wrap and chill in the freezer for about 15 minutes to ensure it stays cold.

In a small saucepan over medium heat, combine the chocolate chips, milk, pinch of salt, and vanilla extract. Stir continuously for about 5 minutes, until the chocolate melts and the mixture thickens enough to coat the back of a spoon. Remove from the heat and stir in the butter. Transfer this filling to a bowl and let cool in the fridge until solid.

Working with one chilled disc at a time, roll out the dough on a floured surface to about 12 inches across, then cut it into 3 x 4.5-inch rectangles — you should get about nine pieces. Place these back in the fridge to chill while you preheat your oven to 375℉.

On a parchment-lined baking sheet, lay out four rectangles. Spoon 1 tablespoon of the chocolate filling onto the center of four rectangles, leaving a margin around the edges. Brush the edges with egg wash, place a second rectangle on top, and pinch to seal tightly. Crimp the edges with a fork and poke holes in the top to allow steam to escape.

After a short chill (another 10-20 minutes), brush the pop tarts with egg wash and sprinkle them with sugar. Bake for 19-24 minutes until the crust turns lightly golden and is firm when tapped. Let them cool completely on a rack.

For that iconic S'mores experience, top the cooled pop tarts with a generous layer of chocolate filling, chill again briefly, and prepare the homemade marshmallow topping following a Swiss meringue recipe. Transfer it to a piping bag and pipe on the marshmallow. Use a kitchen torch to toast each pop tart, topping with extra graham cracker crumbs for added texture and flavor.