01 -
Preheat the oven to 165°C. Line a 23cm square baking pan with parchment paper on all sides. Arrange graham crackers in a single layer along the bottom of the pan, breaking them into quarters as needed to fit. Set aside.
02 -
In a heavy-bottomed saucepan over medium-low heat, melt the butter and finely chopped chocolate, stirring constantly until smooth and fully melted. Remove from heat to cool slightly.
03 -
In a stand mixer fitted with the whisk attachment, beat the sugar and eggs together until fluffy and pale yellow in color. Scrape down the bowl and pour in the chocolate-butter mixture. Beat until homogenous, then scrape down the sides and add the vanilla. Mix well until the mixture appears glossy.
04 -
Add both flours, baking powder, and salt, mixing until just combined with no streaks of flour remaining. Avoid overmixing.
05 -
Use a rubber spatula to spread the batter evenly over the graham crackers in your prepared pan, ensuring it reaches all the way to the edges. Bake for 25-30 minutes or until a knife inserted into the center comes out mostly clean and the edges are set. Transfer to a wire rack to cool completely.
06 -
Once the brownies are completely cooled, spoon the marshmallow fluff over the top, creating decorative swirls and spreading it all the way to the edges.
07 -
For a classic s'mores finish, use a culinary torch to toast the marshmallow fluff. Alternatively, place the brownies under a broiler for 1-2 minutes, watching carefully to prevent burning.
08 -
Refrigerate for one hour to set before slicing into 9 large or 16 small brownies. Clean your knife between cuts for neat edges.