1. Preheat oven to 350°
2. Line a 9-inch square pan with parchment paper. Lightly grease with cooking spray. Set aside.
3. In a medium bowl,combine ground graham crackers, sugar, and salt. Add melted butter and fold together until mixture is moistened. Transfer mixture to prepared square pan.
Press into an even layer.
4. Bake for 10 minutes. Remove from oven and set aside.
5. In a medium sauce pan combine the chopped chocolate and sweetened condense milk together over medium-low heat and stir until melted. Pour immediately onto crust.
6. Place in the fridge while making the marshmallow topping.
7. Beat egg whites together until light and frothy using an electric stand mixer with the whisk attachment. With the mixer running, slowly pour in 2 tablespoons sugar; beat until soft peaks form.
8. Combine sugar, corn syrup, water and salt in a small saucepan over medium-high heat. Boil together until a candy thermometer reads 240°.
9. Turn mixer onto low and drizzle the syrup along the side of the bowl slowly combining it into the egg whites. When all the syrup has been added turn mixer up to medium high and beat for 7 minutes until thick and glossy. When there is about one minute left add in the vanilla.
10. Spread the marshmallow topping evenly over the chocolate fudge layer.
11. Place the pan under the broiler and broil for 1 minute, or until lightly golden. Alternatively, use a kitchen torch to gently torch the marshmallow layer until lightly golden.
12. Refrigerate the pan for at least 1 hour before cutting into squares and serving. The squares can be stored in an airtight container in the refrigerator for up to 5 days.
13. Use a very sharp knife to cut the bars. It’s also best if you run the knife under hot water and dry it just before cutting into the bars, and clean it off after each cut. Serve bars with cold glasses of milk.