Heat a large pot over medium heat and add the butter.
Once butter has melted, stir in all but 1 cup of the mini marshmallows. Continue cooking and stirring until the marshmallows have melted. Remove from the heat as soon as the mixture has melted.
Stir the cereal into the marshmallow and keep stirring to coat.
Add the chocolate chips and remaining cup of marshmallows to the mixture and stir well.
Press the mixture into a greased 9x13 baking dish. Spray a piece of wax or parchment paper with nonstick spray and place that over the bars. Use your hands to press the bars into a smooth surface.
Break apart the Hershey’s bar and arrange over the top of the bars, pressing lightly so they stick.
Let cool for 1 hour before cutting and serving.
Notes
We use mini marshmallows, but you can also use full sized marshmallows for melting. One 10 ounce bag plus 1 cup of mini marshmallows is what you’ll need.Press a few extra marshmallows on top, if desired, to give it more of a s’mores look.