In the bowl of a stand mixer fitted with a whisk attachment (thoroughly cleaned and grease free) add the egg whites and cream of tartar. Set aside.

In a medium sized heavy bottom saucepan add the corn syrup, sugar and water. Heat the mixture over low heat stirring constantly until the sugar dissolves, about 2 minutes. Once the sugar has dissolved, bring to a simmer and insert a candy thermometer. (This tool is essential in this recipe).

Allow the mixture to simmer until the thermometer reads 240℉ (120℃), about 7 minutes.

Once your sugar mixture has reached the desired temperature, remove it from the heat and set aside.

With the mixer on medium speed, whip the egg whites until you achieve soft peaks, around 3 minutes.

Very slowly and carefully pour the sugar syrup into the whites in a thin, steady stream. (If your sugar mix has firmed up , put it back on the heat to liquify it).

Once all of the syrup is in, increase the speed to medium-high and continue whipping for 6-8 minutes or until the mixture is thick and glossy. (The whites will deflate at first, but they will eventually thicken and fluff up).

Add in the vanilla extract and continue whipping until the fluff has cooled completely.

Use your marshmallow fluff to decorate cakes or cupcakes. Store leftovers in an airtight container at room temperature for up to 6 weeks.