Spray a 13x9 inch baking dish with non stick spray. Set aside.
In a large microwave safe bowl combine jumbo marshmallows and butter pieces. Microwave for 6 seconds. Remove and stir well until melted and smooth. If necessary, heat at 20 second intervals to fully melt.
6 Tablespoons unsalted butter, 10 oz jumbo marshmallows
Stir in vanilla extract.
1 teaspoon vanilla extract
Add cereal and mix until well coated.
8 cups Golden Grahams cereal
Stir in chocolate chips and mini marshmallows and mix until evenly incorporated.
1 cup mini marshmallows, 1 cup semi-sweet chocolate chips
Press into prepared baking pan. Spray spatula with non-stick spray and press into an even layer.
Top with broken Hershey pieces, gently pressing into the bars so they stick.
2 Hershey Bars
Let everything cool for about 2 hours before slicing to serve