6 tablespoons unsalted butter, melted
1 1/2 cups crushed graham cracker crumbs
2 tablespoons sugar
Pinch fine salt
The original recipe called for from-scratch brownies. In the interest of time I used a box mix.
4 cups large marshmallows. Regular sized marshmallows didn't melt enough, I think the mini ones might be better.
Position a rack in the lower third of the oven and heat oven to 325 degrees F. Line an 8 by-8-inch square baking pan with foil so it hangs over the edges by about 1 inch.
For the crust: Lightly butter the foil with some of the melted butter. Stir the rest of the butter together with the crumbs, sugar, and salt in a medium bowl. Press the crumb mixture evenly over the bottom of the pan. Bake until golden brown, about 20 minutes.
Meanwhile, make the brownie mix. Pour batter into the prepared pan. Bake until the top is crispy and a toothpick inserted into the middle comes out mostly clean, with a few crumbs, about 40 to 45 minutes.
Remove from the oven and carefully position a rack about 6 inches from the broiler and preheat on low. Layer marshmallows across the top and toast under the broiler until golden, - I left them in 1 minute - watch carefully. Gently removing the brownies from the pan using the aluminum flaps. Cool on a rack for as long as you can stand to wait before cutting them and digging in.