I believe this came from Maida Heater’s cookbook.
The Best Marshmallow Recipe
We tried all sorts of recipes for marshmallows until we found this one. Great for bored kids.
Line a 9 x 13 x 2 pan with parchment paper, oil sides, dust bottom with cornstarch and icing sugar mixed.
Put
½ cup water in mixer bowl.
Sprinkle
3 Tablespoons gelatin over the top, mix and set aside.
Put in pan and stir until boiling:
2 cups sugar
¾ cup corn syrup
¼ teaspoon salt
½ cup water
Cover for 3 minutes, and then uncover. Cook to 240 degrees.
Beating at medium speed, pour syrup slowly into the gelatin mix.
After all the syrup has been added, beat at high for 15 minutes
until mixture is lukewarm and marshmallowy.
Add vanilla at end, from 1 tsp to more if you like more.
Let stand 8-12 hours. Then cut into 1” strips, using more cornstarch
and icing sugar as needed.