Preheat oven to 350 degrees. Line cookie sheets with silicone mat or parchment paper.
In a medium bowl, combine graham cracker crumbs, flour, cornstarch, baking powder and salt. Set aside.
In a large mixing bowl, cream butter and sugar until light and fluffy, about 3-4 minutes.
Add egg and extract and mix until well incorporated.
Pour in graham-flour mixture and beat until dough comes together. DO NOT OVERMIX.
Divide dough into 2 portions and wrap in waxed paper. Pace in refrigerator for about 2 hours.
Remove one batch at a time and roll out on a well-floured surface to ¼” thickness. I like to flour the roller or the top of the dough so it doesn’t tear the dough.
Cut into shapes with a pumpkin cut-out.
Take half of pumpkins and cut little triangle eyes and a spooky mouth.
Place on prepared cookie sheets and bake for 11-12 minutes.
Cool a few minutes on cookie sheets then remove to wire racks to cool completely.
Prepare the chocolate coating by placing chocolate chips and shortening in a microwave-safe bowl. Melt in microwave in 30-second increments, stirring in-between until completed melted.
Dip the top of the cookies without cutouts into the chocolate and place on waxed paper or silicon mats, with chocolate side up, to set. (I also tried the chocolate on the bottom and that worked as well.)
Now spread the marshmallow fluff on the back side of the cookies with cutouts and press the fluff side onto one of the chocolate coated cookies.
Feel free to decorate the eyes with little black sprinkles.
Let them set for a little then place in a single layer on a platter so they don't stick together.
Makes about 12-16 sandwich cookies
Notes
Note: The chocolate can be on the inside or the outside of the bottom cookie. Just let it set and either way it will be delicious!TIPS FOR MAKING THE BEST S'MORES COOKIESChill - Don't skip the step to chill the dough. It helps the cookies hold their shape during baking.RemoveQuickly - Only let the cookies cool for a few minutes so they are easy to remove from the baking sheet.Sandwiching - Press the cookies together lightly after adding the marshmallow fluff so the cookies don't crack.