Preheat Oven:

Preheat your oven to 350°F (175°C).

Grease a 12-cup muffin tin or line it with cupcake liners.

Prepare the Cookie Dough :

In a medium bowl, whisk together graham cracker crumbs, flour, baking soda, and salt. Set aside.

In a large mixing bowl, beat the softened butter, brown sugar, and granulated sugar until light and fluffy (about 2-3 minutes).

Add the egg and vanilla extract, mixing until well combined.

Gradually add the dry ingredients to the wet ingredients, mixing until fully combined.

Shape the Dough :

Scoop about 1 tablespoon of dough into each muffin cup.

Use your fingers or the back of a spoon to press the dough evenly into the bottom of each cup, forming a shallow cookie cup.

Bake the Cookie Cups:

Bake the cookie cups for 8-10 minutes, or until they are just beginning to turn golden around the edges.

Remove them from the oven but leave them in the muffin tin.

Add the Marshmallows:

Place half a marshmallow, cut side down, on top of each cookie cup.

Return the muffin tin to the oven and bake for an additional 2-3 minutes, or until the marshmallows are soft and puffed but not browned.

Add the Chocolate:

As soon as you remove the cookie cups from the oven, press a piece of Hershey's chocolate into the center of each marshmallow.

Cool and Serve:

Allow the cookie cups to cool in the muffin tin for about 10 minutes before transferring them to a wire rack to cool completely.

Enjoy warm or at room temperature!