In the bowl of a stand mixer fitted with a whisk, sprinkle the gelatin over the cold water. Let sit.
Place the Stevia In The Raw® in a small bowl and mix 1 tablespoon water into the stevia until it looks like soft marshmallow. Set aside.
Place the sugar and corn syrup in a heavy medium-sized saucepan. Add ⅓ cup water. Cook over medium heat until the mixture boils and registers 225° F on an instant-read or candy thermometer, about 5 minutes. Continue boiling the sugar and when it reaches 235° F (about 3 more minutes) start watching it carefully. When the thermometer registers 240° F – “soft ball” stage – about 3 more minutes, immediately remove the pot from the heat.
Promptly start beating the softened gelatin at medium speed and carefully pour the hot sugar syrup slowly down the side of the bowl in a thin stream. Add the stevia and vanilla. Increase the speed to high and beat until the mixture triples in volume and looks like Italian meringue or well-beaten whipped cream, 5-6 minutes. The creme will flow from the bottom of the whisk in an even, thick column.
If not using Marshmallow Creme immediately, pack it into a plastic container, cover tightly, and store at room temperature for up to 2 days.
Note: Because the syrup is only a small amount, tip the pot to get an accurate temperature reading. This is easier to do when using an instant-read thermometer vs. a candy thermometer clipped onto the side of the pot.