- 1In the bowl of an electric mixer, sprinkle gelatin over 1/2 cup cold water. Let rest for 10 minutes.
- 2Combine sugar, corn syrup, and 1/4 cup water in a small saucepan. Bring to a rolling boil and let cook for 1 minute. Pour boiling syrup into gelatin and mix at high speed. Add the salt and beat for 12 minutes. Add vanilla and incorporate into mixture.
- 3Scrape into a 9-by-9-inch pan lined with oiled plastic wrap and spread evenly. (Note: Lightly oil hands and spatula or bowl scraper.) After pouring marshmallow mixture into the pan, take another piece of plastic wrap and press mixture into the pan.
- 4Let mixture sit for a few hours. Remove from pan, dredge the marshmallow slab with powdered sugar, and cut into nine 3-inch-square pieces with kitchen scissors or a very sharp knife. Dredge each piece of marshmallow in powdered sugar.