Preheat your oven to 350°F (175°C). In a mixing bowl, combine the graham cracker crumbs with melted butter until the mixture resembles damp sand. Press this mixture evenly into the bottom of your baking pan to form a crust.
Bake the crust for about 8-10 minutes until set and fragrant, then remove it from the oven and set aside to cool slightly.
In a microwave-safe bowl, melt the chocolate chips in 30-second bursts, stirring between each until smooth and glossy. Pour the melted chocolate over the cooled crust, spreading it evenly with a spatula.
Sprinkle the mini marshmallows evenly over the chocolate layer, covering all the way to the edges.
Bake the assembled bars for another 8-10 minutes, or until the marshmallows are puffed up and golden brown, filling your kitchen with a toasted marshmallow aroma.
Remove the pan from the oven and allow the bars to cool completely at room temperature, or chill in the fridge for at least 2 hours to set firmly.
Once cooled, cut into squares using a sharp knife. For cleaner cuts, wipe the knife clean between slices.
Optionally, top with additional crushed graham crackers, a drizzle of melted chocolate, or a sprinkle of sea salt for added flavor and texture.
Serve the gooey, sticky bars with a fork or your fingers, and enjoy the irresistible combination of crispy crust, melty chocolate, and toasted marshmallows.
