01 -
Preheat oven to 175°C. Line a 20x20 cm baking pan with aluminum foil, leaving an overhang for easy removal.
02 -
In a food processor, blend graham crackers, sugar, and salt into fine crumbs. Add melted butter and pulse until mixture is evenly moistened. Firmly press into the base of the prepared pan.
03 -
Bake the crust for 10 minutes. Remove from oven and chill in the refrigerator while you prepare the fudge layer.
04 -
In a small saucepan over medium-low heat, combine chocolate chips and sweetened condensed milk. Stir constantly until melted and smooth. Immediately pour the chocolate mixture over the cooled crust and spread evenly. Refrigerate while preparing the topping.
05 -
In a stand mixer fitted with a whisk attachment, beat egg whites and cream of tartar on medium-high speed until soft peaks form, about 7 minutes.
06 -
In a small saucepan over medium-high heat, combine sugar, corn syrup, water, and salt. Bring to a boil and cook until a candy thermometer reaches 115°C. Remove from heat immediately.
07 -
With the mixer on low, gradually pour the hot syrup in a thin stream along the side of the bowl into the whipped egg whites. Increase speed to medium-high and whip until thick, glossy, and resembling marshmallow fluff, 6–7 minutes. Beat in vanilla extract.
08 -
Spread the marshmallow topping evenly over the chilled fudge layer.
09 -
Using a kitchen torch, carefully toast the marshmallow surface until golden brown. Alternatively, broil under a hot oven for approximately 30 seconds, watching closely.
10 -
Refrigerate for at least 1 hour. Lift bars out of the pan using the foil. Cut into squares using a hot, clean knife. Serve chilled or at room temperature. Store in an airtight container in the refrigerator for up to 5 days.