Preheat the oven to 350°F and line a loaf pan with parchment paper. Spray nonstick cooking spray along the sides of the pan.

Whisk together the pumpkin puree, eggs, pumpkin spice, and cinnamon until smooth.

Add the cake mix and stir until just combined, being careful not to over mix.

Pour the batter into the prepared loaf pan.

Bake for 55 to 65 minutes, until a toothpick inserted into the center of the loaf comes out clean.

Let the cake cool for 10 minutes in the pan, then move to a wire rack to cool completely.