Step 1: Get Preheated
Preheat your oven to 350°F (175°C). Line an 8×8 or 9×9-inch baking pan with parchment paper, leaving a bit of overhang for easy lifting.

Step 2: Make the Crust
In a medium bowl, stir together the graham cracker crumbs and sugar. Pour in the melted butter and mix until everything looks like wet sand. Press the mixture firmly into the bottom of the prepared pan to form an even layer. Bake for 8–10 minutes, just until it starts to set. Let it cool slightly while you make the chocolate.

Step 3: Melt the Chocolate Goodness
In a small saucepan over low heat, combine the sweetened condensed milk, chocolate chips, vanilla extract, and a pinch of salt. Stir constantly until everything is melted, smooth, and glossy. This only takes a few minutes, so don’t wander off. Pour the chocolate mixture over the cooled crust and spread it evenly.

Step 4: Marshmallow Mayhem
Sprinkle the mini marshmallows generously on top of the chocolate layer. Go ahead and really pile them on—this is hot chocolate fantasy land, after all.

Step 5: Bake and Toast
Pop the whole thing back into the oven for 5–7 minutes, just until the marshmallows puff up and get lightly golden. If you want a deeper toast (hello, s’mores vibes), turn on the broiler for 1–2 minutes—but watch like a hawk so they don’t burn!

Step 6: Chill, Slice, Devour
Let the bars cool completely, then chill them in the fridge for 1–2 hours to set. Use the parchment to lift them out, slice into squares, and serve. Bonus points for serving with hot chocolate on the side, because we’re not here to hold back.