Mix together flour, salt, cinnamon, baking soda, and baking powder. Set aside.
Break up the graham crackers into small pieces. Be careful to not let it get too powdery, but some graham cracker powder is okay. Set aside.
Cream the butter and sugars together until fluffy.
Slowly add the egg and yolk one at a time, then the vanilla. Beat well, then slowly add the flour mixture and beat until just incorporated.
Fold in the graham crackers, chocolate, and mini marshmallows.
Take a tablespoon of the cookie and create a small indentation.
Stuff 4 - 5- mini marshmallows into the indentation. Make sure they are TIGHTLY packed in. Top with another 2 teaspoons of cookie dough and press together until the dough completely covers the marshmallows. Repeat with the remaining dough and marshmallows. Top the finished cookies with additional chocolate and/or marshmallows to make them prettier, if desired!
Place the cookies on a baking sheet and cover. Cover with plastic wrap and chill in the refrigerator for at least an hour, preferably overnight, up to three days.
Preheat the oven to 350°F.
Uncover the cookies and bake for 8 - 9 minutes or until a light golden brown.
Use a spatula to remove the cookies to cool on a wire rack. For the best results, place the cookies near a fan to cool them quickly.
Serve immediately or store in an airtight container and enjoy within 24 hours.
If you want to learn how to cheat this recipe, take a look at the note below this recipe!
Cheat the recipe: Roll the cookie dough without the marshmallows into balls 2 tablespoons big. Bake for 8 - 10 minutes. Once cooled, toast marshmallows and use the cookies to sandwich them.
Some readers said they prefer sandwiching a large marshmallow with two small squares of graham crackers to help prevent the marshmallow from disappearing.