In the bowl of an electric mixer sprinkle gelatin over ⅓ cup cold water to soften. Prepare a large piping bag fitted with a #868 French star tip; set aside.
In a small saucepan over medium-high heat dissolve granulated sugar in ¼ cup water, stirring. Remove spoon; with a pastry brush, brush inside edges of pan with water to remove sugar crystals and boil until the temperature reaches the soft-ball stage (238ºF) on a candy thermometer. Pour mixture into gelatin without scraping pan, and whisk on medium speed for 3 min. Increase speed to high and whisk until soft peaks form, 8 to 10 min.
Transfer marshmallow to prepared piping bag and immediately pipe dollops onto the tops of the cupcakes; use your finger to stop the flow of marshmallow from the piping tip and to create a flat top for each pumpkin. (Pipe just 5 pumpkins at a time so marshmallow doesn’t set before you decorate.) Working quickly, add licorice pastel “stems” and coat generously with sanding sugar. Allow pumpkins to set about 1 hr before serving; store covered up to a day.
Marshmallow is piped onto cupcakes and covered in crunchy orange sugar. Make cupcakes from a mix or your favorite recipe. Easiest pumpkin patch you’ve ever grown!