Place your chopped Hershey bars or chocolate chunks into the freezer. Freeze at least 20 minutes.

Line an 8"x 8" pan with foil, ensuring there is a little overhang on the sides. Grease the foil with butter or cooking spray.

In a medium sized saucepan ( I used a 2-quart size), melt the butter and 5 cups of mini marshmallows over medium heat until melted and smooth.

Turn off the heat and stir in vanilla and salt.

Combine the cereal, 1 cup of mini marshmallows, and frozen chocolate pieces in a large bowl. Try to keep the chocolate hidden under the cereal to prevent immediate meltage when the hot marshmallow mixture hits.

Pour melted marshmallows over the cereal mixture.

Using a greased rubber spatula, fold everything together quickly until all ingredients are evenly coated in the melted marshmallow goo.

Using a piece of parchment paper or plastic wrap, press s'mores mixture into the prepared 8"x8" pan until it's evenly distributed and compact.

Add the remaining mini marshmallows to the top of the bars and spread into an even, single layer.

To "roast" the marshmallows: Move your oven rack 3 rows down from the top of the oven. Set the broiler to high.

Place the baking dish under the broiler, leave the oven door cracked open so you can watch the marshmallows. DO NOT TAKE YOUR EYES OFF THAT PAN. 

Broil for 45 seconds to 1 minute until the top marshmallows are golden brown and roasted.

Remove s'mores bars from oven and let sit at room temp for at least 2 hours.

Using your foil overhangs, gently remove the bars from the pan and set on a cutting board.

Take off the foil and discard. Cut bars into 12 squares, using a knife that has been greased with butter or sprayed with cooking spray.

Store in an airtight container for up to 3 days.