Preheat your oven to 350°F.
Line a 9x13 baking dish with parchment paper or lightly grease the pan.
In a mixing bowl, stir together the graham cracker crumbs and melted butter until the crumbs look evenly coated.
Press the mixture firmly into the bottom of the baking pan to create an even crust.
Bake for 8 minutes.
Remove the crust from the oven and immediately sprinkle the chocolate chips evenly over the warm crust.
Let them sit for about a minute so they begin to soften.
Scatter the mini marshmallows over the chocolate layer.
Return the pan to the oven and bake for 15–20 minutes, or until the marshmallows are golden brown and toasted on top.
Let the bars cool completely before cutting.
