Prepare a sheet tray with parchment paper and spray with cooking spray. In the bowl of a stand mixer fitted with the whisk attachment, hydrate gelatin packets with ice cold water.
Combine warm water, sugar, and corn syrup in a sauce pot. Gently stir to combine. Place over medium high heat and cook until sugar mixture has reached 250°F.
Turn stand mixer on low and slowly drizzle hot sugar mixture down the side of the bowl. Once all of the syrup is incorporated add vanilla and salt. Increase speed to high and beat mixture until thick, white, and the bowl feels lukewarm, about 10 minutes.
While the marshmallow is being whipped, combine powdered sugar and corn. Dust prepared sheet tray with some of this mixture, set aside what remains.
Take a pastry bag fitted with a round or star tip and fold down the sides twice. Use a pastry brush to paint stripes of food color on the inner walls of the bag.
Transfer finished marshmallow to painted pastry bag. Pipe marshmallow onto prepared sheet tray in large rounds or desired shape. Dust with remaining powdered sugar mixture.
Allow to dry ambiently for 3 days. Store in an airtight container for up to a month.
Heating the sugar up to 250°F creates a firmer marshmallow that is perfect for toasting!
Change up the extract to create other flavors such as maple or rum.
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