Ingredients:

  • 1 ½ cups Graham Cracker Crumbs
  • ¼ cup Granulated Sugar (for crust)
  • 6 tablespoons Unsalted Butter, melted (for crust)
  • 1 ¾ cups All-Purpose Flour
  • 1 teaspoon Baking Soda
  • ½ teaspoon Salt
  • ½ cup Unsalted Butter, softened (for dough)
  • ¾ cup Light Brown Sugar, packed
  • ½ cup Granulated Sugar (for dough)
  • 1 large Egg
  • 1 teaspoon Vanilla Extract
  • 1 cup Semi-Sweet Chocolate Chips
  • 5 cups Marshmallows (approx. 10 oz / 300g)

Instructions:

  1. Preheat oven to 350°F (175°C). Line a 9x13 inch pan with parchment paper, ensuring an overhang on two sides to create a sling for easy removal later.
  2. Make the Crust: In a bowl, combine graham cracker crumbs and ¼ cup sugar. Pour in the 6 tablespoons of melted butter and mix until evenly moistened. Press this mixture firmly and evenly into the bottom of the prepared pan. Bake for 8 minutes; remove and set aside.
  3. Make the Cookie Dough: Whisk together flour, baking soda, and salt in a small bowl. In a large bowl, cream the ½ cup softened butter and both sugars until light and fluffy (about 3 minutes). Beat in the egg and vanilla until just combined.
  4. Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just incorporated—do not overmix.
  5. Assemble Layers: Crumble about two-thirds (2/3) of the cookie dough evenly over the pre-baked crust. Sprinkle the chocolate chips evenly over this layer. Dollop the remaining one-third (1/3) of the dough randomly over the chocolate layer.
  6. Bake the base and cookie layers for 18–22 minutes, or until the edges are golden brown and the centre is set but still slightly soft.
  7. Remove the bars from the oven. Immediately arrange the 5 cups of marshmallows evenly over the hot surface.
  8. Toast the Topping: Switch the oven setting to Broil (High). Place the pan on the upper-middle rack. Broil for 2–4 minutes, watching constantly, until the marshmallows are puffy and perfectly golden brown.
  9. Cool and Slice: Remove from the oven. Let the bars cool completely (at least 2 hours) before using the parchment sling to lift them out and slice into 16 squares.