3 packs of unflavored gelatin
1 c. cold water, divided
1 1/2 c. sugar
1 c. light corn syrup
1/4t. kosher salt
1t. pure vanilla extract
1/4c. confectioners’ sugar
1/4 c. constarch
1. Place the gelatin into the bowl of a stand mixer along with 1/2 cup of the water.
2. In a small saucepan combine the remaining 1/2 c. water, sugar, corn syrup & salt. Place over medium high heat, cover and allow to cook for 3-4 minutes. uncover, clip a candy thermometer onto the side of the pan and continue to cook until the mixture reaches 240 degree F, approximately 7-8 minutes. Once the mixture reaches this temperature, immediately remove from the heat.
3. With the whisk attachment on low-speed slowly pour the sugar syrup down the sides of the bowl into the gelatin mixture. Once you have added all of the syrup, increased the speed to high. Continue to whip until the mixture becomes very thick and is lukewarm, approximately 12-15 minutes. Add the vanilla during the last-minute of whipping. While the mixture is whipping prepare the pan as follows.
4. Combine the confectioners’ sugar & cornstarch in a small bowl. Lightly spray a 13×9 inch metal baking pan with nonstick cooking spray. Add the confectioners’ sugar mixture & move it around to completely coat the bottom & sides of the pan.
5. Pour the mixture into the prepare pan, using a lightly oiled spatula for spread evenly into the pan. Dust the top with remaining confectioners’ sugar mixture. Allow the marshmallows to sit covered with waxed paper for @ least 4 hrs. or overnight.
6. Turn the candy out onto a cutting board and cut into 1-inch squares using a pizza wheel dusted with the confectioners sugar mixture. Once cut, lightly dust all the marshmallows, use additional sugar if necessary. Store in an airtight container for up to 3 weeks.