6 T. unsalted Butter, melted
1 1/2 C. crushed graham cracker crumbs
2 T. Sugar
Pinch of fine Salt
8 T. (1 stick) unsalted Butter
4 oz. unsweetened chocolate, chopped
1 C. packed light brown sugar
3/4 C. white sugar
1 1/2 tsp. pure vanilla extract
1/2 tsp. fine salt
4 large cold eggs
1 C. Flour
4 C. large marshmallows
Position a rack in the lower third of the oven and heat oven to 325º Line a 8x8 square baking pan with oil so it hangs over the edges by an 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. Put the butter and chocolate in a med. microwave safe bowl. Melt in the microwave for 2 minutes. Stir, and microwave again until completely melted, about 2 more minutes. Alternatively, put the butter and chocolate in a heat proof bowl. Bring a saucepan filled with 1 inch or so of water to a very slow simmer; set the bowl on the pan with out touching the water. Stir occasionally until melted. Stir the light brown and white sugars, vanilla and salt into the melted chocolate. Add the eggs and beat vigorously to make a thick and glossy batter. Add the flour and stir until just incorporated.
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 40-45 minutes.
Remove from the oven and carefully posting a rack about 6 inches from the broiler and preheat on low. Layer marshmallow across the top and toast under the broiler until golden. (keep an eye on it, it can go quick), about 2 minutes. Cool on a rack, gently removing the brownies from the pan using the aluminum flaps. Carefully separate any marshmallows from the foil and fold away. Cut into 12 (2 inch) squares.