Preheat the oven to 180C/350F. Line an 8 x 8-inch pan with parchment paper and set aside.
In a mixing bowl, whisk together the spice cake mix and pumpkin puree until smooth.
Transfer the batter into the lined pan and bake for 25-27 minutes, or until a skewer comes out clean.
Remove the cake from the oven and let it cool completely, before frosting.
Notes
TO STORE: Store the cake in an airtight container at room temperature for up to three days. If you want to keep it fresher for longer, keep it in the refrigerator for up to one week. TO FREEZE: Wrap leftover cake slices in plastic wrap, store them in an airtight container, and freeze them for up to six months.