Line 2 baking sheets with parchment paper.
Prepare pipping bag with Wilton 1M pipping tip. Place pipping bag into tall glass or pitcher.
In a saucepan add water and agar. Stir well with the whisk.
Add granulated sugar, glucose syrup and pumpkin puree.
Mix with whisk and cook over medium heat. As soon as it starts boiling, set timer for 5 minutes.
Continue cooking syrup, whisking a few times. Syrup should be thicker after 5 minutes boiling. Syrup should be at 217-221oF (102-105oC) if you want to check with thermometer. When syrup is ready, remove from the heat.
Meanwhile, start making meringue. In a mixing bowl of stand mixer with whisk attachment, add egg whites.
Beat on low speed untill foamy then add granulated sugar. Whip on medium speed untill soft peacks form.
Slowly pour the sugar syrup into the meringue, while mixer running on medium high speed. Do not pour syrup into whisk, aim it toward the side of the bowl.
When all syrup is poured in, increase the speed to high and whip for 2 minutes.
Transfer the mixture into the prepared pipping bag.
Pipe 2-inch round rosettes on the prepared baking sheet.
Let Pumpkin Zephyr Marshmallow to set for 4-5 hours.
Dust with powdered sugar (optional).