Preheat oven to broil.
Grease a 9x13 baking dish, and line a baking sheet with foil and grease the foil.
Place the rice cereal and all but ¼ cup (if you can, try tosave the larger broken pieces to decorate the top) of thecrushed graham crackers. Mix it together well.
Spread half of the mini marshmallows onto the baking sheet and broil for a minute or two. You want the marshmallows to look lightly toasted, but not burned. They will burn easily so keep an eye on them. Set aside.
You can turn off the oven for a few minutes while you move on to the next step.
In a large saucepan, melt the butter. Then, add in the large marshmallows and stir until completely smooth and melted.
Pour the melted marshmallows onto the rice krispies, and scrape the toasted marshmallows in too. Mix well.
Spread the marshmallow mixture into the greased 9x13 pan in an even layer. Don’t press too hard or you will ahve dense bars and they won’t be as soft and chewy. You may find a greased spatula really helpful for this.
Sprinkle the chocolate chips on top of the bars and place in the warm oven to melt the chocolate chips. It should only take 20 seconds or so, do it longer if needed. Use the spatula or the back of a spoon to spread the melted chocolate chips into an even layer.
Turn the broiler back on.
Scatter the remaining mini marshmallows on top of the chocolate and broil for a minute, and then check it every 20-30 seconds after a minute, until it is lightly toasted. You may also want to rotate the pan halfwaythrough to make sure it browns evenly.