Preheat your oven to 350°F. Line a cookie sheet with parchment paper.
In a medium bowl, whisk together the flour, baking powder, baking soda and salt. Set aside.
In a food processor, crush your graham crackers into fine crumbs. A fist, bad day and ziploc bag should work too.
In a large bowl, using an electric hand mixer, beat the butter, sugar and 1/2 cup of the graham cracker crumbs until fluffy, 2 minutes. Add in the egg and vanilla and beat until incorporated. Add the flour mixture in thirds and beat until just combined.
House the remaining graham cracker crumbs in a shallow bowl. Roll your dough into small balls and then coat in the graham crumbs. Bake for 10-12 minutes or; they will start to crack on sides. Remove from oven and turn on the broiler.
Let the cookies cool for 5 minutes and then gently press down a marshmallow half (cut side down) into each cookie. Broil the cookies for 30 seconds until marshmallows edges turn golden. WATCH them - it happens quickly. You may have to rotate the pan halfway through. Remove the pan from the oven and immediately gently insert your Hershey's Kisses into each marshmallow.
Recipe is courtesy of the America's Test Kitchen.I like to eat these warm so that the marshmallow and chocolate are totally gooey.