1Preheat oven to 375.
Whisk together flour, graham cracker crumbs, baking soda and salt. Set aside
2Cream butter, peanut butter and sugars together in a large bowl with a mixer on medium speed until light and fluffy. Beat in egg and vanilla until incorporated. Blend in flour mixture on low speed.
3Scoop dough with #60 scoop (about 1 Tbsp) onto ungreased baking sheets. Bake for 4 minutes. Top each cookie with a marshmallow half and bake another 4-5 minutes until marshmallow is golden. Transfer cookies to cooling rack and press chocolate pieces on top. Let stand 5 minutes.