Preheat your oven to 375°F (190°C). Line two large baking sheets with parchment paper or silicone baking mats and set aside.
Place 8 full graham cracker sheets in a sealed zip-lock bag and crush with a rolling pin into coarse, uneven crumbs — avoid a fine powder. Measure out 1 cup of crumbs and set aside.
In a medium bowl, whisk together the flour, baking soda, and salt until evenly combined. Set aside.
Beat the softened butter, granulated sugar, and brown sugar together on medium-high speed for 3 to 4 minutes until the mixture is light, fluffy, and pale. Scrape down the sides of the bowl as needed.
Add the eggs one at a time, beating for about 30 seconds after each addition, then mix in the vanilla extract until fully combined.
With the mixer on low, add the flour mixture in three additions, mixing just until no flour streaks remain. Do not overmix.
Using a rubber spatula, fold in the crushed graham cracker crumbs and chocolate chips until evenly distributed throughout the dough.
Scoop the dough into 1.5-tablespoon balls and place them 2 inches apart on the prepared baking sheets. Press 3 to 4 mini marshmallows firmly onto the top of each dough ball.
Bake one sheet at a time on the center rack for 10 to 12 minutes, until the edges are set and lightly golden but the centers still look slightly underdone. The marshmallows should be puffed and lightly toasted.
Let the cookies rest on the pan for 5 minutes, then transfer to a wire rack to cool for at least 10 more minutes before serving.