Step 1

Place the cake mix and pumpkin pie spice in a large bowl and whisk to combine and break up any lumps. Add the pumpkin purée, oil, and eggs, and mix with a wooden spoon or an electric hand mixer on medium speed until the dry ingredients are just incorporated without overmixing, about 1 minute. The dough will be sticky, but firm. Cover the bowl and refrigerate the dough for at least 1 hour.

Step 2

Arrange 2 racks to divide the oven into thirds and heat to 350°F. Line 2 baking sheets with parchment paper or a silicone baking mat.

Step 3

Using a spoon or cookie scoop, measure out 1 1/2 tablespoons of dough. Roll into a ball in the palm of your hands and place on the prepared baking sheets, about 2 inches apart.

Step 4

Bake for 5 minutes. Rotate the baking sheets between racks and from front to back. Bake until the cookies are light golden-brown on the bottom, 4 to 5 minutes more. Let the cookies cool on the baking sheet for 2 to 3 minutes, then use a flat spatula to transfer to them to a wire rack to cool completely. Meanwhile, make the frosting.

Step 5

Place the cream cheese and butter in the bowl of a stand mixer fitted with the paddle attachment. (Alternatively, use an electric hand mixer and large bowl.) Beat on medium speed until combined, about 20 seconds. Gradually beat in the powdered sugar and vanilla until the frosting starts to come together into lumps. Increase the speed to high and beat until fluffy and creamy, scraping down the sides of the bowl as needed, about 30 seconds.

Step 6

Generously spread the frosting onto the cooled cookies. Sprinkle with extra pumpkin pie spice or sprinkles.