These bars have never lasted for more than a few hours in my house, and for good reason: They bring the popular combo of chocolate, graham crackers, and marshmallows to the table in the form of an easy-to-eat cookie.
1½cupsfinely ground graham cracker crumbs (about 5 double graham crackers)
¾cupall-purpose flour or gluten-free flour blendsuch as Bob’s Red Mill 1-to-1 Baking Flour
½cupbrown sugarfirmly packed
Pinchof kosher salt
½cupcold unsalted buttercut into ½-inch cubes
1large egglightly beaten
Topping
⅔cupheavy cream
12ouncesdark chocolate chips or chunkssuch as Guittard or Callebaut
2cupsminiature marshmallows
⅓cupchopped walnutstoasted (optional)
Flaky saltfor garnish (optional)
Instructions
Preheat the oven to 350°F (175°C). Line a 9-inch (23-cm) square baking pan with parchment paper.
For the crust: To the bowl of a food processor fitted with the metal blade, add the graham cracker crumbs, flour, brown sugar, and salt. Pulse a few times to incorporate. Add the butter pieces and process until the mixture resembles coarse meal, then add the egg and pulse a few times until the mixture sticks together.
Transfer the mixture to the prepared pan and, using lightly buttered fingers, press evenly into the bottom to form a crust. Alternatively, use the flat bottom of a measuring cup or glass to press the mixture into the pan.
Bake until golden brown and just firm to the touch, 18 to 20 minutes. Let cool completely in the pan on a wire rack, about 30 minutes.
For the topping: In a medium saucepan, bring the cream to a simmer over medium-low heat (do not boil). Remove from the heat, add the chocolate, and whisk until melted and smooth. Stir in the marshmallows and the walnuts, if using. Spread the mixture evenly over the crust, then cover and refrigerate until firm, about 2 hours.
Use the parchment to lift the sheet from the pan, then cut the bars into 2-inch (5-cm) squares. Sprinkle with a little flaky salt, if desired.
Notes
To store: Remove from the parchment, arrange in a single layer in an airtight container, and refrigerate for up to 3 days.