01 - Preheat the oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together the gluten-free flour, baking soda, and salt until well blended.
03 - In a large bowl, beat the softened butter, brown sugar, and granulated sugar until light and creamy, about 2-3 minutes.
04 - Add the egg and vanilla extract to the butter mixture. Beat until fully combined and smooth.
05 - Gradually add the dry ingredients to the wet mixture, mixing until just combined. Do not overmix.
06 - Gently fold in the chocolate chips, mini marshmallows, and graham cracker pieces until evenly distributed.
07 - Using a heaping tablespoon or cookie scoop, drop dough balls onto the prepared baking sheets, spacing them about 2 inches apart.
08 - Bake for 10-12 minutes, or until edges are golden brown and centers are just set.
09 - Cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.