The use of cocoa powder gives this a great chocolate flavor without making it overly sweet, given the addition of marshmallows twice. Use semi-sweet or dark chocolate chips to give it another depth of flavor.
While this is melting, grease a 13x9 pan with butter on the bottoms and sides. Add your Golden Grahams to a large bowl.
8 cups Golden Grahams
Once your marshmallows have melted, remove from the heat. Add the cocoa powder and stir until incorporated. Add the vanilla and do the same.
1/4 cup cocoa powder, 1 teaspoon vanilla
Immediately pour the marshmallow mixture over the cereal and stir gently to avoid crushing cereal where possible.
Once it is mostly mixed together, add chocolate chips and mini marshmallows. Stir again until all the cereal is thoroughly coated and the extra ingredients are distributed evenly throughout.
1 cup chocolate chips, 1 cup mini marshmallows
Pour the mixture into your greased 13x9 pan and gently use your (greased) fingers to spread into an even layer throughout the pan. Let harden in the pan at room temperature for at least two hours.
Cut with a sharp knife when ready to serve. This will store at room temperature, tightly sealed, for up to three days.