In the bowl of a stand mixer fitted with the whisk attachment, add ½ cup of the cold water and gelatin. Immediately stir together with a spoon so it doesn’t clump. Set aside.
In a medium saucepan, add the cane sugar, honey, the ½ cup warm water, pumpkin spice, and sea salt. Put over high heat and stir with a high heat spatula until all the sugar has dissolved and you have a liquid. Periodically stir the sugar mixture until it starts to bubble and rise up. Remove from the heat and pour directly over the gelatin in the mixing bowl.
Start mixing on low and gradually increase the speed as the mixture starts to thicken. It will start out as an opaque color and slowly it will start to lighten in color as it thickens. Keep increasing the speed until you are at full speed.
Continue mixing on high until the mixture is a thick consistency and resembles marshmallow fluff. It should be sticky and hold its shape for a short period of time. The entire mixing time should be about 10 to 15 minutes.
Line a 9x13-inch baking pan with parchment paper. Grease the prepared parchment paper and two additional sides of the baking dish with avocado oil spray.
On a baking sheet with parchment paper, or a work surface, sift a generous amount of powdered sugar. Slowly pull at the ends of the marshmallow that are not against the parchment paper so it’s not stuck to the pan. Lift the entire marshmallow out of the pan and turn it upside down onto the powdered sugar. Sift more powdered sugar on top.
Using a pizza cutter (this is a great trick, but a sharp knife will do as well), cut into 24 squares (six by four). You can leave as large marshmallows or cut each square into four pieces for mini marshmallows.
Roll each side in the powdered sugar to keep from sticking together. Allow them to sit out overnight before storing so the powdered sugar can form to the sides and they won’t stick together.
Store in an airtight container for up to 2 weeks.