Lightly spray the bottom and sides of a 9X13X2 or 11X15X1 pan, and then wipe the pan out, leaving only a very thin film of oil. Using a sifter, layer the bottom of the pan with a fairly thick layer of marshmallow coating (you might consider adding 1½ t ginger, 1 t cinnamon and ¾ t cloves to the basic coating recipe for a gingerbread spiced coating; I did so for one of my batches). Let it hit the sides and corners of the pan as much as possible. Set aside.
Measure your ½ cup water and whisk it with the pumpkin puree. Dump the gelatin into a medium sized bowl and set the pumpkin puree mix beside it.
Place the remaining ½ cup water, marshmallow syrup, salt and sugar into a heavy 4 qt pan--in that order. Stir twice. Bring to a boil over medium high heat; while waiting, whisk together the pumpkin puree mix with the gelatin and dump it into the bowl of your stand mixer. Set the mixer bowl in the mixer and attach the whip.
When the syrup boils, place a lid over it for 2 minutes to prevent crystals. Then remove the lid and increase the heat to high. Attach a candy thermometer to the side of the pan. Heat the boiling sugar mixture to 255 F; do not stir.
When it reaches 255 F, remove the thermometer and turn off the heat. Moving quickly but very carefully, pour the syrup into the mixer bowl with the mixer running on low speed. Slowly increase the speed to high and place a towel over the mixer to prevent being hit by splattering liquid. Whip on high for 10 minutes. Slow the mixer down to a medium low speed and add the spices. Increase the speed back up to high and whip one more minute.
After adding the spices and mixing the additional minute, lower your bowl (I like to do this with the mixer running as it helps remove some of the fluff from the whip attachment). Have a large spatula ready. Turn off the mixer--working quickly now--and remove the whip attachment, knocking as much fluff as possible back into the bowl (do not get too hung up on this, you are going to lose some fluff no matter what). Using the spatula, scrape the fluff into the prepared pan and smooth it as evenly as possible. Set aside, uncovered, to set for 4-6 hours.
When the marshmallows have set, use a table knife to gently loosen the marshmallow cake from the sides of the pan. Sprinkle your marshmallow coating over a cutting board--I like a large wooden one. Using your fingers (you're going to get messy, just have clean hands and accept it) or a flexible turner, loosen the marshmallow cake from the bottom of the pan. Once you are certain it is loose, use both hands to gently remove the cake and place it on the prepared cutting board. (This step was so easy with this recipe.) Using a chef's knife, slice the marshmallows into squares. You may need to occasionally clean your knife or dredge it in the coating powder. Roll each marshmallow in the coating powder before storing, in a single layer, for up to a week.
I plan to acquire a 11 X 15 baking pan so I can make thinner marshmallows--and then I would like to slice this recipe in the shape of pumpkins and other Halloween appropriate shapes with cookie cutters. I have not tried it yet--it needs the larger pan so the marshmallow cake is thinner, more like the thickness of the cookie cutter, which should not be thinner than the marshmallow cake--but if you try it let me know how it turns out!
Recipe by The Spiced Life at https://www.thespicedlife.com/pumpkin-pie-marshmallows/