Combine the flour, salt, baking soda, cinnamon, graham cracker crumbs, and cornstarch in a bowl then whisk together and set aside.
Using a stand or hand mixer, beat butter and sugars in a bowl until creamy, about 2 minutes. Add in egg and vanilla and until combined. Scrape the bowl down and mix once more.
Gradually add flour mixture to butter mixture, beating on low speed until just combined.
Reserve a handful of the marshmallows and set aside then add the remaining marshmallows, chocolate chips, and Graham crackers to the dough and mix on low until just combined (do not over-beat).
Portion out roughly two tablespoon sized pieces of dough. Roll into balls. Refrigerate dough for an hour or more.
Heat oven to 350F and place cookies on a parchment-lined baking sheet, spacing about 2 inches apart.
Top with reserved pieces of milk chocolate and marshmallows. Bake at 350° for 12 minutes. IF a some cookies had a blowout because of a few too many marshmallows to you can corral them back together with a spoon or a knife.
Leave on pan to cool completely.
Notes
Sofia's Tips:
In order to master the texture of this cookie, it is super important that you don’t add too much flour! Adding too much flour is easy to do and often results in a cookie that is hard and dry.
To correctly measure your flour, use a spoon to generously fill a measuring cup with flour. Once filled, use a knife to level off the top of the measuring cup!
An extra sprinkle of sea salt on the tops of these cookies goes a long way to enhance their flavour!
If your marshmallows have blown out from the cookies during baking, once baked and on the cookie sheet - gently tuck in the marshmallows back into the cookie to give the cookie a nice, rounded appearance. *this step is best done while the cookie is still warm.
Allow the freshly baked cookies to cool on the baking sheet until the base has firmed up and the cookie can maintain its shape. At that point you can transfer the cookie to a wire rack to cool completely.
Have you tried this recipe!? I would love to know what you think! Leave a comment below! 🙂