Homemade Marshmallows
 
Ingredients
  • ⅓ cup powdered sugar
  • 3 Tablespoons cornstarch
  • ¾ oz unflavored gelatin (3 x ¼ oz packets)
  • 1 cup cold water, divided
  • 1 cup light corn syrup
  • 1½ cups granulated sugar
  • ¼ teaspoon salt
  • 1 Tablespoon vanilla extract
Instructions
  1. Read through this entire recipe before starting so you know generally what is coming next. Also read the notes for information about candy thermometer readings.
  2. Mix the powdered sugar and cornstarch together and then sift.
  3. Spray the bottom and sides of a 9 x 13 in glass or ceramic baking pan with cooking spray. Liberally sprinkle some of the sugar and cornstarch mixture that you made in step #2 on to the bottom and sides of the pan. Don't be shy! The rest of the sugar and cornstarch mixture will be used in step #13.
  4. Place the gelatin and ½ cup cold water in a stand mixer (do not use a hand mixer) and mix with the whisk attachment. Set aside while you make the syrup.
  5. In a 3 qt saucepan over medium heat, cook the remaining ½ cup of water, corn syrup, granulated sugar, and salt.
  6. Stir the mixture with a wooden spoon until the sugar has dissolved.
  7. Attach a candy thermometer to the pot but don't let it touch the bottom of the pan. You may have to hold it with a hot pad.
  8. Cook the mixture without stirring (it will be boiling) until it reaches 240°F or the correct temperature for your thermometer.**
  9. Take the syrup off the stove and carefully pour the hot syrup into the gelatin mixture. Turn the mixer on to high speed. Do this quickly because as the syrup cools it hardens quickly into a very hard glass like consistency. Immediately rinse or soak any spoon you have used.
  10. Beat the mixture in the mixer for 10-15 minutes until it is thick, white, and glossy. Mix the vanilla in during the last minute of mixing.
  11. Spoon the mixture into the prepared pan and try to smooth out the top with a rubber spatula.
  12. Let sit uncovered at room temperature for at least 6 hours.
  13. Cover your counter with wax paper and generously coat the wax paper with the rest of the powdered sugar and cornstarch mixture.
  14. Loosen the marshmallow slab from the pan and flip it on to the wax paper.
  15. Coat the upper side with some of the powdered sugar and cornstarch to make it not sticky.
  16. Using a sharp knife dusted with powdered sugar and cornstarch, cut the marshmallow slab into squares.
  17. Coat the edges with powdered sugar and cornstarch so they aren't sticky.
Store at room temperature for a week in an air tight container.
Notes
**Candy Thermometers: Candy thermometers can be extremely unreliable. To see if yours is accurate, boil water and test if it is 212°F with your candy thermometer. If it's not, don't worry! Just adjust the temperature in this recipe to fit your thermometer. So if your water boils at 202°F adjust the 240°F needed down to 230°F.

To clean your pots and bowls: For the pot you made the syrup in, boil water in it and then immediately dump the hot water down the drain. All the glued on syrup should come off. For anything else, get the hottest water going in your sink and run the gooped areas directly under the steaming hot water.
Recipe by Birch Tree Baking at https://www.birchtreebaking.com/homemade-marshmallows/