Adapted from Alton Brown
1/4 cup confectioners’ sugar
1/4 cup cornstarch
3 packages unflavored gelatin
1 cup ice cold water, divided
12 ounces granulated sugar, approximately 1 1/2 cups
1 cup light corn syrup
1/4 teaspoon kosher salt
1 teaspoon Gluten Free vanilla extract
Additional Gluten Free Flavorings or food colors, as desired
Spray the pan heavily with cooking spray (or grease with shortening if you prefer). Mix cornstarch and powdered sugar in a separate bowl. Pour about half the mixture into the pan and shake around the coat. Over wax paper, tap out any excess powder. Picking the wax paper up, return the excess powder to the bowl.
Fit your stand mixer with its whisk attachment. Pour the gelatin and ½ cup of the ice water into its bowl. Allow to sit as you continue to make the marshmallow syrup. In a small saucepan combine: 1/2 cup water, granulated sugar, corn syrup and salt. Cover and cook on medium or medium high heat for about 3 minutes. No need to stir.
Take the lid of the syrup, and attach your candy thermometer to the side of the pan. Continue to boil for about 7 minutes until the syrup reaches 240 degrees and remove from heat immediately.
Put your stand mixer on low speed churning the gelatin mixture for a few turns and then, while running, SLOWLY pour the syrup down the side of the bowl. When all the syrup is incorporated, increase to a high speed. I cover the stand mixer with a tea towel for the first few minutes to prevent hot syrup from flying around my kitchen. Continue to whip until the mixture becomes very thick and is lukewarm, approximately 12 -13 minutes. Add the vanilla, and other flavors or colors, if using, during the last minute of whipping.
Pour the marshmallow cream into the prepared pan.
If you have a powdered sugar shaker, shake a bit of powdered sugar to coat slightly. Then take a few tablespoons of the powdered mixtures and brush on over top of the marshmallows. Allow to sit for 4 hours or overnight. Keep the remainder of the powder mixture.
When you cut the marshmallows, dip each side in the powder sugar mixture to keep it them from sticking to everything & Enjoy!