Heat oven to 375° F. Spray 12-count muffin pan with cooking spray and set aside.
In small bowl combine flour, graham cracker crumbs, corn starch, baking soda, and salt.
In large bowl beat butter, brown sugar, granulated sugar, and vanilla until creamy. Add egg and beat well. Gradually add in dry ingredients and mix well. Stir in chocolate chips.
Use cookie scoop or tablespoon to add about two tablespoons of cookie dough to each muffin tin. Use hands to flatten dough. Add about one tablespoon of marshmallow creme on top of the dough. Evenly disperse the remaining cookie dough and add on top of the marshmallow creme.
Bake cookies 15 minutes or until golden brown. Let cool and use plastic knife to remove from muffin pan.