Preheat the oven to 350 degrees and line cookie sheets with parchment paper. Place the graham crackers in a Ziploc bag and crush them using a rolling pin.

Melt the butter in a large bowl. Whisk in the granulated sugar and the brown sugar.

Add the dry ingredients (flour, baking soda, salt, graham cracker crumbs) to the butter and sugar mixture. Next, add the egg and vanilla. Mix well with an electric mixer.

Use a spatula or wooden spoon to fold in the chocolate chips. Scoop the dough into 8 equal size cookie dough balls with a cookie scoop or tablespoon. Flatten each ball into a disc and place on the parchment lined baking sheet.

Bake cookies in the preheated oven for 10 minutes. You'll know that they're ready to come out of the oven when the edges are just starting to brown.

Remove from oven and immediately press 5-6 mini marshmallows into the top of each cookie.

Change the oven setting to broil and place one sheet of cookies back in the oven for just a minute or two, until the marshmallows are toasted to a golden brown. Remove promptly and place the cookies on a cooling rack. There's no need to cool completely - just until the marshmallow is set.