1️⃣ Preheat the oven to 350°F (175°C). Line an 8×8-inch baking pan with foil. 🔥

2️⃣ Place the graham crackers, sugar, and salt in the bowl of a food processor and pulse until finely ground. Add the melted butter and pulse until the mixture is moistened. Press the mixture into the bottom of the prepared baking pan. Bake for 10 minutes. Place the pan on a heat pad in the fridge to cool while you prepare the filling. 🍪

3️⃣ In a small heavy-bottomed saucepan set over medium-low heat, combine the chocolate chips and condensed milk. Stirring constantly, heat until the mixture is melted, thick, and smooth. Pour over graham cracker crust. Place in the refrigerator while making the marshmallow topping. 🍫

4️⃣ In the bowl of an electric mixer fitted with the whisk attachment, beat the egg whites and cream of tartar until soft peaks form, about 7 minutes. 🥚

5️⃣ Meanwhile, in a small saucepan set over medium-high heat, combine the sugar, corn syrup, water, and salt. Bring the mixture to a boil and continue to cook until a candy thermometer registers exactly 240°F, about 8 minutes. Immediately remove from heat. 🍬

6️⃣ Turn the mixer on low speed and slowly but continuously add the syrup, pouring it between the side of the bowl and whisk. Increase speed to medium-high and beat until the mixture is very thick and looks like marshmallow fluff, about 6-7 minutes longer. Add vanilla and beat until combined. 🍥

7️⃣ Spread the marshmallow topping evenly over the chocolate fudge layer. Use a kitchen torch to gently torch the marshmallow layer until lightly golden. Alternatively, place the pan under the broiler and broil for about 30 seconds, or until lightly golden, checking on it every few seconds (it can burn quickly!). 🔥

8️⃣ 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. ❄️