S'mores icebox cookies
1 h 30 min
1 1/2 cups
, at room temperature
, for filling
STIR flour and graham cracker crumbs with baking powder and salt in a medium bowl. Add 1/2 cup mini chocolate chips to crumb mixture.
BEAT butter with sugar in a large bowl, using an electric mixer on medium-high, until fluffy. Beat in egg and vanilla. Gradually beat in flour mixture, just until combined. Gather into a ball. Dough will be crumbly. Scoop out of mixing bowl and quickly roll into 1 log. Wrap logs in wax paper and twist ends. Chill until firm, 1 to 1 1/2 hours. Slice chilled dough 1/8 in thick.
POSITION racks in top and bottom thirds of oven. Preheat to 350F. Line 2 baking sheets with parchment.
ARRANGE 1 inch apart on prepared sheets. Bake in top and bottom thirds of oven, switching halfway through, until cookies are golden, 10 to 12 min. Let cookies cool on sheets for 1 min, then transfer to a wire rack to cool completely. Let cookies cool on sheet for 1 min. Transfer to a rack to cool completely. Sandwich 1 tbsp marshmallow fluff between 2 cookies. Repeat with remaining dough. Cookies will keep well, stored in an airtight container at room temperature, up to 5 days.