In a large bowl or stand mixer, cream together sugars and butter until smooth. Beat in egg and vanilla, scrape bowl as needed. Mix in salt, baking soda, baking powder and flours until no streaks remain. Mix in graham cracker pieces by hand. Cover and chill until firm, roughly 2-4 hours.
Preheat oven to 350°F. Line a baking sheet with a silicone baking mat. Using a medium cookie scoop, place dough 2 inches apart. Bake for 13-15 minutes or until edges are just golden brown. Immediately transfer to a wire rack to cool completely.
When cookies have cooled completely, prepare marshmallow filling.
In a medium heat proof bowl over simmering water, whisk together egg whites, sugar and cream of tartar. Continue whisking until sugar has dissolved completely and egg whites are warm to the touch. Transfer to a stand mixer, with whisk attachment, whisk on medium-high speed until stiff peaks form. Mix in vanilla in the last 30 seconds. Transfer mixture to a large piping bag fit with desired piping tip. Alternately a large plastic bag may be used with the tip snipped off.
Pipe marshmallow frosting onto flat side of one cookie, press another cookie on top to form a sandwich. Repeat with remaining marshmallow frosting and cookie halves. Use a kitchen torch to lightly char the frosting.
Nutritional information is provided as a courtesy and is an estimate only. Nutrition information can vary for a variety of reasons. For the most accurate data, use your preferred nutrition calculator with the actual ingredients you used to make this recipe.
Did you make this recipe?I'd love to see it! Snap a picture and tag @bakedbyrachel on Instagram!