FOR THE BROWNIE BASE
2 large eggs
1/2 cup plus 2 tablespoons | 55 g dutch process cocoa
1/2 teaspoon medium grain kosher salt
1/2 teaspoon baking powder
1/2 teaspoon espresso powder
2 teaspoons vanilla extract
1/2 cup | 115 g unsalted butter
1 cup plus 2 tablespoons | 225 g sugar
3/4 cup | 95 g all-purpose flour
FOR THE GRAHAM CRUNCH AND GANACHE
2 tablespoons water
2 tablespoons granulated sugar
8 graham crackers
8 ounces | 225 g bittersweet chocolate, 70% cocoa solids
1/4 teaspoon espresso powder, optional
A good pinch medium grain kosher salt
2/3 cup | 160 ml heavy cream
FOR THE MARSHMALLOW FROSTING
4 egg whites
1 cup | 200 g granulated sugar, preferably toasted
1/4 teaspoon cream of tartar
A good pinch medium grain kosher salt
Seeds scraped from a vanilla bean, or 2 teaspoons pure vanilla extract
Make the brownies. Preheat an oven to 325°F | 165°C.
Lightly grease an 8-inch square baking tin, then line with a piece of parchment paper with a 1-inch overhang. Press the paper into the pan and then remove. Line the pan with another piece of parchment paper, then place the first piece, buttered side up, across. Set aside.
Crack the eggs into a bowl. Sift in the cocoa, baking powder, espresso powder, and salt. Add the vanilla. Beat for four minutes on medium speed (you can do this while melting the butter in the next step).
Place the remaining butter in a medium saucepan. Pour in the sugar. Heat over medium low, stirring, until the butter is melted. Continue to cook until the mixture is hot but not bubbling, maybe 1 minute more. It should go shinier as it heats.
Stir the hot butter and sugar mixture into the beaten eggs until smooth. Sift the flour over top and mix it in.
Spread the batter into the baking dish, nudging it to the edges as needed. Bake until the top begins to crack, 32 to 35 minutes or so. Cool on a wire rack.
While that bakes, make the graham crunch and ganache. Line a rimmed baking sheet with parchment paper. In a small, heavy bottomed saucepan, dissolve the sugar into the water. Bring to a boil over medium heat then simmer for 5 minutes. Brush both sides of the graham crackers with the syrup then arrange on the prepared baking sheet (there will be syrup left over. Save it as a sweetener for coffee, oatmeal, or fruit). Bake the crackers until toasted, 8 to 10 minutes, flipping once. Set aside to cool then snap into pieces, some small, some large bite-sized.
Tumble the chopped chocolate, espresso powder, and salt in a large heatproof bowl. Heat the cream in a medium, heavy-bottomed saucepan. Once steaming, pour the cream over the chocolate and let stand 5 minutes, undisturbed. After the time is up, stir until smooth, starting at the centre of the bowl and working outwards. Fold in the graham crunch. Pour the rubbled ganache over the brownies and spread to an even layer. Cool to room temperature, then refrigerate until set.
Finally, make the frosting. In the bowl of a stand mixer, stir together the egg whites, sugar, cream of tartar, and salt. Set the bowl over a saucepan of simmering water, making sure that the bowl has some clearance. Heat, stirring attentively and scraping down the sides of the bowl periodically with a silicone spatula, until the mixture reaches 175°F | 80°C on a candy thermometer, about 8 minutes. Transfer the whites to the stand mixer with the wire whisk attached. Beat, starting slow and increasing the speed steadily, until the mixer is on full. Whip until the stiff, glossy peaks form, 5 to 7 minutes. Stir in the vanilla.
Retrieve the brownies from the fridge. Spoon the frosting onto the ganache layer. Use an offset spatula or the back of a spoon to swoop and swirl it to your liking. Toast the frosting with a culinary torch or under a hot broiler—watching it all the while. Let cool and set, then use the cross of parchment to lift the brownies from the pan, then slice and serve. Extras can be refrigerated in their pan, loosely covered with cling film, for 2 days. Or, frozen until firm and then transferred to an airtight container for freezer storage up to a month.
I also really like Jenny Rosenstrach's brownies from her book How to Celebrate Everyting: Recipes and Rituals for Birthdays, Holidays, Family Dinners, and Every Day In Between (Ballantine, 2016). You'll find them on page 95. They are one of me most-perfectly textured brownies I've ever had. They are slightly thinner than my brownies, which is why I went for the King Arthur for those looking to replicate the look of the photo.