Spray a 9- x 13-inch pan with non stick spray and line with Gefen Parchment Paper. Sift a thick coating of icing sugar over the bottom of the pan.
2. Pour 3/4 cup of water into a mixer bowl and sprinkle the gelatin over the water. Let it sit for about five minutes and add the vanilla bean seeds and salt.
3. Put remaining 1/2 cup water, sugar, and corn syrup in a medium saucepan. Cook, stirring, over low heat until the sugar dissolves. Set your candy thermometer in the pot, and turn heat to high. Bring to a boil without stirring until the syrup reaches 244 degrees Fahrenheit. (If your syrup turns amber colored, do not throw out, it can still work and your marshmallows will have a caramel flavor)
4. With the mixer on medium low speed, slowly pour hot syrup down the side of the bowl into the gelatin mixture. Turn mixer to high and beat for a full 10 minutes.
5. Working with a greased spatula, pour marshmallow into your pan and smooth the top. Sift a thick layer of icing sugar over the entire top and let sit at room temperature for 12 hours.
6. Turn over marshmallows and, using a knife coated with non stick spray, cut into one-inch squares. Throw the squares into a zip-lock bag with icing sugar and toss until the marshmallows are all coated and not sticking to each other.