Preheat your oven to 350°F. In a large bowl, blend together the egg, spice cake mix, and 1 cup canned pumpkin puree until the mixture is well combined. You can use a spoon or an electric mixer for this step. The dough will be quite sticky.

Line a baking sheet with parchment paper. Using a 1.5 tablespoon-sized cookie scoop, spoon portions of dough onto the sheet. Spray the back of a measuring cup or large spoon with non-stick spray, then flatten each cookie. It's helpful to reapply spray between cookies since the dough is sticky. Optionally, sprinkle granulated sugar on top for extra sweetness. Bake in the preheated oven for 9-12 minutes or until the cookies are soft and springy. Allow the cookies to cool completely before serving or storing.

In a large bowl, combine the heavy cream, whole milk, 1 cup pumpkin puree, brown sugar, vanilla extract, and pumpkin pie spice. Use a hand mixer or stand mixer to blend the mixture until smooth and homogenous. This step serves as the base for either the churned or no-churn ice cream method.

If using an ice cream maker, freeze the bowl overnight beforehand. Transfer the blended ice cream mixture to your ice cream maker and churn according to the manufacturer's instructions, about 25 minutes for KitchenAid. For a soft serve texture, enjoy immediately; for a firmer texture, freeze the churned ice cream in a metal loaf pan or freezer-safe container for at least 4 hours. If making no-churn ice cream, chill a mixing bowl and whisk attachment in the freezer for 20-30 minutes. Whip the heavy cream separately until stiff peaks form, gently fold in the pumpkin mixture, then transfer to a loaf pan or container, cover, and freeze for 4 hours or overnight. I like to let my ice cream sit out for a couple of minutes before scooping—it makes serving easier and creamier.

Serve the cooled cookies as they are, or pair them with scoops of homemade pumpkin ice cream for a delightful fall dessert. Store leftover cookies in an airtight container with parchment between layers to prevent sticking. For the ice cream, keep covered in the freezer until ready to enjoy.