Combine the flour, graham cracker crumbs, baking soda and salt in a medium sized bowl and set aside.

Cream the butter and sugars together in a large mixer bowl on medium speed until light in color and fluffy. Scrape down the sides of the bowl while it’s mixing a few times, as needed. You should be able to see the change in color and texture happen and know it’s ready.

Add the egg and egg yolk one at a time and mix until well combined after each addition.

Add the vanilla extract and mix until well combined.

Add the dry ingredients and mix until the dough is just combined. Do not over mix. It will be thick.

Add the milk and combine on low speed just until incorporated. Use a rubber spatula to finish combining the dough and help it come together. Add an additional teaspoon of milk only if really needed to help the dough come together. You don’t want to add too much liquid and end up with cookies that spread too much.

Stir in the chocolate chips, chopped graham crackers and 1 cup of mini marshmallows.

Scoop and roll 2 tablespoon-sized balls of cookie dough until all the cookie dough has been used.

Place cookie dough balls onto cookie sheet and bake for 5-6 minutes, or until the cookies are starting to flatten out, but aren’t fully flat. Then, open the oven and carefully place a few pieces of chopped Hershey’s bar and a few of the remaining mini marshmallows on top of each cookie. Bake cookies for another 2-3 minutes, until cookies are golden and marshmallows are slightly melty.

Remove cookies from the oven and allow to cool on baking sheets for 5-10 minutes before transferring to a wire rack to cool completely. If the cookies have spread a little more than you like or some marshmallows got unruly, you can use a spoon to gently push the sides in a bit.

These cookies are at their best when warm, but can be stored in an airtight container for 3-4 days.