Pumpkin Spice Marshmallows (adapted from 17 And Baking) - Approximately 40 marshmallows
1. Using a light cooking oil like vegetable or canola, grease a 9" x 13" glass baking dish and liberally dust with sifted powdered sugar. Set aside.
2. In a mixing bowl, whisk together pumpkin puree and spices until well incorporated. Set aside.
3. In a separate large mixing bowl, or the bowl of your stand mixer, add 1/2 cup of cold water. Pour gelatin powder over water and let sit for 10 minutes. Meanwhile in a medium saucepan, mix sugar, corn syrup, and the additional 1/4 cup of water. Heat over medium-high heat until mixture comes to a boil and a candy thermometer reads 250 degrees. (This is the “hardball” stage, where balls form and keep their shape when water is dropped into the boiling sugar. Be careful not to overheat the mixture.)
4. Immediately turn on mixer and beat gelatin on low speed, adding in the hot sugar combination slowly. Once combined, add salt and increase mixer speed to medium, being very careful not to beat so fast that the hot contents fly about. Beat until the mixture increases in volume and begins to fluff, about 10 additional minutes. Once a thick puff forms, beat in vanilla and set aside.
5. Gently fold in pumpkin into the marshmallow mixture and transfer to the greased pan. Let it sit at room temperature overnight, uncovered or loosely topped with paper towels.
6. When ready to cut, invert pan on a well-dusted powdered sugar surface. Let rest upside-down for about a minute, then gently pull pan to let the large marshmallow block fall. Using a butcher’s knife, cut into desired pieces. Dust with additional powdered sugar to keep marshmallows from sticking.