Preheat the oven to 350 degrees F. Line two cookie sheets with parchment paper.In the bowl of a stand mixer, add butter and both sugars. Mix until light and fluffy; about 2 minutes. Add the egg and vanilla. Mix again until combined.
In a separate bowl, add the flour, graham cracker crumbs, baking powder and salt. Whisk together until combined. (Using a whisk helps to sift the flour.)Slowly mix in these dry ingredients into the wet ingredients, on low speed, until the dough is combined.
Fold in the mini marshmallows and chocolate chips.Using a 1.5 inch cookie scoop, drop dough onto prepared cookie sheets. (try to cover the marshmallows with dough as best you can. If they're too exposed they'll melt.)Bake cookies for 12 minutes. Remove from oven and let stand 15 minutes before serving. Enjoy!Yields: 18 cookies