Line an 8x8 inch square baking dish with parchment paper and spray with nonstick cooking spray or coat with butter. Set aside
In a large pot, add butter and melt over medium-low heat, cooking and stirring with a heatproof spatula until the butter is just browned and smells nutty (keep an eye on it and be careful not to cook it too long or it’ll burn).
Turn heat to low. Add marshmallows to pot and stir until marshmallows are completely melted and mixture is smooth.
Stir in vanilla.
Remove from heat, add in Cocoa Krispies and Golden Grahams followed by 1 ½ cups mini marshmallows, stirring well to combine. Mixture will be sticky!
Add half the mixture to the prepared pan.
Using a small square of wax or parchment paper that’s been sprayed with nonstick cooking spray, press down on mixture to form an even layer in the pan.
Sprinkle half the remaining mini marshmallows and half the hershey’s bar pieces on top.
Repeat the layers by adding the remainder of the Cocoa Krispie mixture on top and pressing down, then sprinkling with mini marshmallows and chocolate
Allow to cool then cut into 16 squares.