Start by adding your butter, vanilla, and 6 cups of marshmallows to a pot. Make sure you do this low and slow, so you don’t burn the marshmallows.
Stir continuously until melted down and smooth. Remove from heat and immediately add to your Golden Graham cereal. Stir until everything is evenly coated.
Line a 9x9 baking dish with parchment paper and press half of the mixture into the dish. Top with ½ your remaining marshmallows and half of your Hershey pieces.
Press the rest of your cereal mixture on top. Make sure it is even and flat. Top with remaining marshmallows and Hershey pieces. Let cool to room temperature.
Slice and enjoy!