1. Combine the powdered sugar and cornstarch in a small bowl. Lightly spray a 13 x 9 cookie sheet with cooking spray. Sprinkle with
the powdered sugar mixture to coat the bottom and sides. Save the rest of the sugar mixture for later.

2. Put the gelatin in the stand mixer mixing bowl along with ½ cup cold water. Stir gently.

3. In a small saucepan combine the remaining ½ cup water, sugar, corn syrup, and salt. Cook over medium heat.

4.  Clip a candy thermometer on the side of the saucepan and boil until the temperature reaches 240 degrees, about 10 minutes. Immediately remove from heat.

5.  Turn the stand mixer on low.   Slowly pour in the hot sugar mixture. Once all the sugar mixture is in the bowl, turn the mixer on high.

6.  Continue to mix until your mixture because very thick and is white, about 15 minutes. Add in the vanilla the last minute of mixing.

7. Pour the mixture into the prepared pans, using an oiled spatula to
spread evenly into the pan. At this point I needed to oil my hands in
order to transfer all the mixture to the pans.

8. Dust the top of the marshmallow mixture with the sugar and cornstarch mixture. Let the marshmallows rest uncovered for 4 hours and up to overnight.

9. Turn the marshmallows out onto a cutting board and cut into 1 inch squares using a pizza cutter. Once cut, dip each marshmallow in the remaining sugar and cornstarch mix, covering each cut side.