Recipe by Alton Brown
3 pkgs unflavored gelatin
1 cup ice cold water, divided
1 1/2 cups granulated sugar
1 cup light corn syrup
1/4 tsp salt
1 tsp pure vanilla extract (I used 1 Tbsp)
1/4 cup confectioners sugar
1/4 cup cornstarch
Place the gelatin in the bowl of a stand mixer, add water. Let sit white you prepare the sugar mixture.
In a small sauce pan, combine the remaining half cup of water, the sugar, corn syrup and salt. Place over medium high heat. Cover and cook for about 3 to 4 minutes. Uncover, clip a candy thermometer to the side of the pan and cook until it reaches 240 degrees F approx 7-8 minutes. Once it reaches that temp, immediately remove from heat. Turn the mixer (using a whisk attachment) on low and slowly pour the sugar mixture into the gelatin mixture.Once all the sugar has been added turn mixer to high and whip until the mixture is very thick and lukewarm. Approx 12-14 minutes. Add vanilla during the last minute of mixing. While it's mixing prepare your dish,
Combine the confectioners sugar and cornstarch in a small bowl. Lightly spray a 13X9 baking dish and sprinkle the sugar cornstarch over the pan to coat. Return the rest of sugar back to bowl for later. When ready por the marshmallow mixture into prepared plan use a sprayed spatula to help spread in evenly.Dust the tops with more sugar, cornstarch mixture. Lightly cover with plastic wrap and let sit for 4 hours. After the 4 hours turn onto a cutting board and use a pizza cutter to cut to sizes you want. Dip the cut sides into remaining cornstarch, sugar mixture. Store in airtight container.