Preheat the oven to 350° F and grease the cups of two, 12-cup muffin pans (this recipe makes 24 cookie cups).
In a large bowl with an electric mixer, beat together the butter and the sugars until creamy. Mix in the vanilla, and then add the eggs, one at a time, mixing slowly after each addition.
In a separate bowl, combine the flour, baking soda, and salt. Add this mixture into the butter/sugar mixture slowly, stirring well. Then, fold in two cups of chopped Hershey's chocolate, 1 cup crushed graham crackers and 1 cup of marshmallows, broken into bits. Reserve the whole Hershey's chocolate pieces and marshmallows for topping after they bake.