For these killer treats, make the graham and chocolate layers ahead. Pop the pan in the freezer and chill (at least 4 hours or overnight). When ready to serve — and make sure everyone is around and ready for dessert! — heat the broiler and take the pan out of the freezer. Use the foil to lift onto a cookie sheet, cover with marshmallow halves, broil and serve. Absolutely everyone will love these. Before starting, be sure to read "Baking Together #8: The Make-Ahead S'more You Definitely Want in Your Freezer." When you've made the recipe, leave your comments below. We love baking together.
Tip: Instead of your oven broiler, you could also broil these in your toaster oven.
Makes 18 squares
For the crust:
2/3 cup (2 5/8 ounces) finely ground graham cracker crumbs
1 tablespoon granulated sugar
Pinch of table salt
2 tablespoons (1 ounce) unsalted butter, melted
For the filling:
3 ounces milk chocolate, finely chopped
3 tablespoons heavy cream
2 tablespoons (1 ounce) unsalted butter, cut into 4 pieces
For the topping:
9 marshmallows
Make the crust:
1. Position a rack in the center of the oven and heat the oven to 350°F. Line an 8 ½ x 4 ½ x 2 3/4-inch loaf pan (I use Pyrex) with foil, leaving about a 1-inch overhang on two opposite sides. Lightly grease the foil.
2. Put the graham crumbs, sugar and salt in a small bowl and mix with a fork until blended. Pour the melted butter over the crumbs and mix until well blended and the crumbs are evenly moist. Reserve 2 tablespoons of the mixture and scrape the remaining mixture into the pan. Lay a piece of plastic on top and, with your fingers directly on the plastic, press the crumbs evenly into the bottom of the pan. (A small, flat-bottomed measuring cup works well to ensure the crumbs are tightly packed on the bottom.) Remove the plastic and bake the crust until fragrant, 5 to 7 minutes. Move the pan to a rack and let cool.
Make the filling:
1. Put the chocolate, heavy cream, butter, and salt in a small heatproof bowl and melt over a pan of simmering water (or in a microwave in 10 to 15 second increments), stirring until smooth, about 4 minutes. Remove from the heat and set aside until cooled and slightly thickened, 10-15 minutes. (For faster cooling, set the bowl over a slightly larger bowl filled with ice and a little water.)
2. Scrape the chocolate into the pan and spread evenly. Sprinkle the reserved graham crumbs evenly over the chocolate. Arrange the pan in the freezer (uncovered) so it’s level and freeze until very firm, at least 4 hours or up to 3 days.
Assemble and serve:
1. Using scissors, cut the marshmallows in half crosswise. Heat the broiler to high.
2. Use the foil edges on the sides of the pan to lift the layer from the pan. Set on a cookie sheet and carefully peel away the foil from the sides. Arrange the marshmallows, cut side down, close together on top of the layer to cover it completely. Broil until marshmallows are toasted to your liking, 1 to 2 minutes.
3. Move the foil to a cutting board and cut the layer lengthwise into 3 equal strips then cut each strip into 6 squares. Serve immediately.
Leftovers can be covered and stowed in the refrigerator for up to 3 days. They are best when served chilled.
