Preheat the oven to 350°F. Line baking sheets with parchment paper or leave them ungreased.
In a medium bowl, whisk together 1 ½ cups all-purpose flour, 1 ½ cups coarsely crushed graham crackers, ¼ teaspoon baking powder, and ¼ teaspoon salt. Set aside.
In a large mixing bowl, cream together ½ pound softened butter, ¾ cup brown sugar, and ¾ cup granulated sugar until smooth and well combined.
Add 2 eggs and 1 teaspoon vanilla extract. Beat until fully incorporated.
Gradually add the dry ingredients to the butter mixture and mix just until combined.
Stir in 1 cup chocolate chips until evenly distributed throughout the dough.
Scoop the cookie dough into approximately 2-ounce portions and place them on prepared baking sheets, leaving space between each cookie.
Bake for 8 minutes, then remove the cookies from the oven.
Quickly press 4 mini marshmallows and 2-3 pieces of chopped Hershey chocolate bars into the top of each cookie.
Return the cookies to the oven and bake for an additional 2 minutes, or until the marshmallows are lightly golden and toasted.
Remove from the oven and allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack.
Serve warm or allow them to cool completely before storing in an airtight container.