Yield: Makes 16 to 36 marshmallows (depending on size)
Ingredients
⅔ cup water, divided
¾ ounces unflavored gelatin
1 cup granulated sugar
1 cup light corn syrup
Pinch of kosher salt
1 teaspoon vanilla extract
1 cup confectioners' sugar, for dusting
Directions
Lightly oil the inside of an 8 by 8-inch pan (mine was slightly bigger) with vegetable oil. Generously coat with confectioners' sugar and set aside.
Pour ⅓ cup of the water into a bowl. Sprinkle the gelatin over the water and set aside.
In a saucepan combine the remaining ⅓ cup water with the sugar, corn syrup, and salt. Place over medium-high heat and cook until it reaches 240F on a candy thermometer.
Very carefully add the hot syrup to the softened gelatin.
Add the vanilla and mix for 8 to 13 minutes, until the mixture becomes very white, stiff, and sticky. (A stand mixer is really the best tool for the job but I used an old-fashioned hand beater and a lot of elbow grease.)
Spread the mixture into the prepared pan using a lightly oiled spatula. Set aside for at least 1 hour, or until the marshmallows are firm and cool.
Run a wet knife around the edge of the pan to loosen the marshmallow sheet and remove it from the pan.
Using a sharp, wet knife, cut into squares.
Toss each marshmallow in the confectioners' sugar until completely coated (or use cocoa powder or shredded coconut!).
Store separated by parchment or wax paper in a container. They should keep for at least a month. Do not refrigerate.
Notes
Gluten Free, Parve, Vegan, and Vegetarian (with animal product-free gelatin)
Recipe by Katherine Martinelli at http://www.katherinemartinelli.com/blog/2012/homemade-marshmallows/